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2022-03-21powerpc/pseries: Fix use after free in remove_phb_dynamic()Michael Ellerman
In remove_phb_dynamic() we use &phb->io_resource, after we've called device_unregister(&host_bridge->dev). But the unregister may have freed phb, because pcibios_free_controller_deferred() is the release function for the host_bridge. If there are no outstanding references when we call device_unregister() then phb will be freed out from under us. This has gone mainly unnoticed, but with slub_debug and page_poison enabled it can lead to a crash: PID: 7574 TASK: c0000000d492cb80 CPU: 13 COMMAND: "drmgr" #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc #1 [c0000000e4f075d0] oops_end at c000000000029608 #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4 #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8 #4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30 Data SLB Access [380] exception frame: R0: c000000000167250 R1: c0000000e4f07a00 R2: c000000002a46100 R3: c000000002b39ce8 R4: 00000000000000c0 R5: 00000000000000a9 R6: 3894674d000000c0 R7: 0000000000000000 R8: 00000000000000ff R9: 0000000000000100 R10: 6b6b6b6b6b6b6b6b R11: 0000000000008000 R12: c00000000023da80 R13: c0000009ffd38b00 R14: 0000000000000000 R15: 000000011c87f0f0 R16: 0000000000000006 R17: 0000000000000003 R18: 0000000000000002 R19: 0000000000000004 R20: 0000000000000005 R21: 000000011c87ede8 R22: 000000011c87c5a8 R23: 000000011c87d3a0 R24: 0000000000000000 R25: 0000000000000001 R26: c0000000e4f07cc8 R27: c00000004d1cc400 R28: c0080000031d00e8 R29: c00000004d23d800 R30: c00000004d1d2400 R31: c00000004d1d2540 NIP: c000000000167258 MSR: 8000000000009033 OR3: c000000000e9f474 CTR: 0000000000000000 LR: c000000000167250 XER: 0000000020040003 CCR: 0000000024088420 MQ: 0000000000000000 DAR: 6b6b6b6b6b6b6ba3 DSISR: c0000000e4f07920 Syscall Result: fffffffffffffff2 [NIP : release_resource+56] [LR : release_resource+48] #5 [c0000000e4f07a00] release_resource at c000000000167258 (unreliable) #6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648 #7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io] #8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io] #9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c #10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504 #11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868 #12 [c0000000e4f07c70] new_sync_write at c00000000054339c #13 [c0000000e4f07d10] vfs_write at c000000000546624 #14 [c0000000e4f07d60] ksys_write at c0000000005469f4 #15 [c0000000e4f07db0] system_call_exception at c000000000030840 #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168 To avoid it, we can take a reference to the host_bridge->dev until we're done using phb. Then when we drop the reference the phb will be freed. Fixes: 2dd9c11b9d4d ("powerpc/pseries: use pci_host_bridge.release_fn() to kfree(phb)") Reported-by: David Dai <zdai@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Sachin Sant <sachinp@linux.ibm.com> Link: https://lore.kernel.org/r/20220318034219.1188008-1-mpe@ellerman.id.au
2022-03-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-16powerpc/time: improve decrementer clockevent processingNicholas Piggin
The stop/shutdown op should not use decrementer_set_next_event because that sets decrementers_next_tb to now + decrementer_max, which means a decrementer interrupt that occurs after that time will call the clockevent event handler unexpectedly. Set next_tb to ~0 here to prevent any clock event call. Init all clockevents to stopped. Then the decrementer clockevent device always has event_handler set and applicable because we know the clock event device was not stopped. So make this call unconditional to show that it is always called. next_tb need not be set to ~0 before the event handler is called because it will stop the clockevent device if there is no other timer. Finally, the timer broadcast interrupt should not modify next_tb because it is not involved with the local decrementer clockevent on this CPU. This doesn't fix a known bug, just tidies the code. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220124143930.3923442-3-npiggin@gmail.com
2022-03-16powerpc/time: Fix KVM host re-arming a timer beyond decrementer rangeNicholas Piggin
If the next host timer is beyond decrementer range, timer_rearm_host_dec will leave decrementer not programmed. This will not cause a problem for the host it will just set the decrementer correctly when the decrementer interrupt hits, it seems safer not to leave the next host decrementer interrupt timing able to be influenced by a guest. This code is only used in the P9 KVM paths so it's unlikely to be hit practically unless large decrementer is force disabled in the host. Fixes: 25aa145856cd ("powerpc/time: add API for KVM to re-arm the host timer/decrementer") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220124143930.3923442-2-npiggin@gmail.com
2022-03-16powerpc/tm: Fix more userspace r13 corruptionNicholas Piggin
Commit cf13435b730a ("powerpc/tm: Fix userspace r13 corruption") fixes a problem in treclaim where a SLB miss can occur on the thread_struct->ckpt_regs while SCRATCH0 is live with the saved user r13 value, clobbering it with the kernel r13 and ultimately resulting in kernel r13 being stored in ckpt_regs. There is an equivalent problem in trechkpt where the user r13 value is loaded into r13 from chkpt_regs to be recheckpointed, but a SLB miss could occur on ckpt_regs accesses after that, which will result in r13 being clobbered with a kernel value and that will get recheckpointed and then restored to user registers. The same memory page is accessed right before this critical window where a SLB miss could cause corruption, so hitting the bug requires the SLB entry be removed within a small window of instructions, which is possible if a SLB related MCE hits there. PAPR also permits the hypervisor to discard this SLB entry (because slb_shadow->persistent is only set to SLB_NUM_BOLTED) although it's not known whether any implementations would do this (KVM does not). So this is an extremely unlikely bug, only found by inspection. Fix this by also storing user r13 in a temporary location on the kernel stack and don't change the r13 register from kernel r13 until the RI=0 critical section that does not fault. The SCRATCH0 change is not strictly part of the fix, it's only used in the RI=0 section so it does not have the same problem as the previous SCRATCH0 bug. Fixes: 98ae22e15b43 ("powerpc: Add helper functions for transactional memory context switching") Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220311024733.48926-1-npiggin@gmail.com
2022-03-16powerpc/xive: fix return value of __setup handlerRandy Dunlap
__setup() handlers should return 1 to obsolete_checksetup() in init/main.c to indicate that the boot option has been handled. A return of 0 causes the boot option/value to be listed as an Unknown kernel parameter and added to init's (limited) argument or environment strings. Also, error return codes don't mean anything to obsolete_checksetup() -- only non-zero (usually 1) or zero. So return 1 from xive_off() and xive_store_eoi_cmdline(). Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller") Fixes: c21ee04f11ae ("powerpc/xive: Add a kernel parameter for StoreEOI") [lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru] Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>: Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220313065936.4363-1-rdunlap@infradead.org
2022-03-15x86/ibt,kprobes: Cure sym+0 equals fentry woesPeter Zijlstra
In order to allow kprobes to skip the ENDBR instructions at sym+0 for X86_KERNEL_IBT builds, change _kprobe_addr() to take an architecture callback to inspect the function at hand and modify the offset if needed. This streamlines the existing interface to cover more cases and require less hooks. Once PowerPC gets fully converted there will only be the one arch hook. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154318.405947704@infradead.org
2022-03-15x86/livepatch: Validate __fentry__ locationPeter Zijlstra
Currently livepatch assumes __fentry__ lives at func+0, which is most likely untrue with IBT on. Instead make it use ftrace_location() by default which both validates and finds the actual ip if there is any in the same symbol. Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154318.285971256@infradead.org
2022-03-11arch: Remove references to CONFIG_NFSD_V3 in the default configsChuck Lever
CONFIG_NFSD_V3 has been removed. NFSD support for NFSv3 can no longer be disabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2022-03-11powerpc/net: Implement powerpc specific csum_shift() to remove branchChristophe Leroy
Today's implementation of csum_shift() leads to branching based on parity of 'offset' 000002f8 <csum_block_add>: 2f8: 70 a5 00 01 andi. r5,r5,1 2fc: 41 a2 00 08 beq 304 <csum_block_add+0xc> 300: 54 84 c0 3e rotlwi r4,r4,24 304: 7c 63 20 14 addc r3,r3,r4 308: 7c 63 01 94 addze r3,r3 30c: 4e 80 00 20 blr Use first bit of 'offset' directly as input of the rotation instead of branching. 000002f8 <csum_block_add>: 2f8: 54 a5 1f 38 rlwinm r5,r5,3,28,28 2fc: 20 a5 00 20 subfic r5,r5,32 300: 5c 84 28 3e rotlw r4,r4,r5 304: 7c 63 20 14 addc r3,r3,r4 308: 7c 63 01 94 addze r3,r3 30c: 4e 80 00 20 blr And change to left shift instead of right shift to skip one more instruction. This has no impact on the final sum. 000002f8 <csum_block_add>: 2f8: 54 a5 1f 38 rlwinm r5,r5,3,28,28 2fc: 5c 84 28 3e rotlw r4,r4,r5 300: 7c 63 20 14 addc r3,r3,r4 304: 7c 63 01 94 addze r3,r3 308: 4e 80 00 20 blr Seems like only powerpc benefits from a branchless implementation. Other main architectures like ARM or X86 get better code with the generic implementation and its branch. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
net/dsa/dsa2.c commit afb3cc1a397d ("net: dsa: unlock the rtnl_mutex when dsa_master_setup() fails") commit e83d56537859 ("net: dsa: replay master state events in dsa_tree_{setup,teardown}_master") https://lore.kernel.org/all/20220307101436.7ae87da0@canb.auug.org.au/ drivers/net/ethernet/intel/ice/ice.h commit 97b0129146b1 ("ice: Fix error with handling of bonding MTU") commit 43113ff73453 ("ice: add TTY for GNSS module for E810T device") https://lore.kernel.org/all/20220310112843.3233bcf1@canb.auug.org.au/ drivers/staging/gdm724x/gdm_lte.c commit fc7f750dc9d1 ("staging: gdm724x: fix use after free in gdm_lte_rx()") commit 4bcc4249b4cf ("staging: Use netif_rx().") https://lore.kernel.org/all/20220308111043.1018a59d@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-10resume_user_mode: Move to resume_user_mode.hEric W. Biederman
Move set_notify_resume and tracehook_notify_resume into resume_user_mode.h. While doing that rename tracehook_notify_resume to resume_user_mode_work. Update all of the places that included tracehook.h for these functions to include resume_user_mode.h instead. Update all of the callers of tracehook_notify_resume to call resume_user_mode_work. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-12-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-03-10ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.hEric W. Biederman
Rename tracehook_report_syscall_{entry,exit} to ptrace_report_syscall_{entry,exit} and place them in ptrace.h There is no longer any generic tracehook infractructure so make these ptrace specific functions ptrace specific. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-3-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-03-09powerpc/papr_scm: Add perf interface supportKajol Jain
Performance monitoring support for papr-scm nvdimm devices via perf interface is added which includes addition of pmu functions like add/del/read/event_init for nvdimm_pmu struture. A new parameter 'priv' in added to the pdev_archdata structure to save nvdimm_pmu device pointer, to handle the unregistering of pmu device. papr_scm_pmu_register function populates the nvdimm_pmu structure with name, capabilities, cpumask along with event handling functions. Finally the populated nvdimm_pmu structure is passed to register the pmu device. Event handling functions internally uses hcall to get events and counter data. Result in power9 machine with 2 nvdimm device: Ex: List all event by perf list command:# perf list nmem nmem0/cache_rh_cnt/ [Kernel PMU event] nmem0/cache_wh_cnt/ [Kernel PMU event] nmem0/cri_res_util/ [Kernel PMU event] nmem0/ctl_res_cnt/ [Kernel PMU event] nmem0/ctl_res_tm/ [Kernel PMU event] nmem0/fast_w_cnt/ [Kernel PMU event] nmem0/host_l_cnt/ [Kernel PMU event] nmem0/host_l_dur/ [Kernel PMU event] nmem0/host_s_cnt/ [Kernel PMU event] nmem0/host_s_dur/ [Kernel PMU event] nmem0/med_r_cnt/ [Kernel PMU event] nmem0/med_r_dur/ [Kernel PMU event] nmem0/med_w_cnt/ [Kernel PMU event] nmem0/med_w_dur/ [Kernel PMU event] nmem0/mem_life/ [Kernel PMU event] nmem0/poweron_secs/ [Kernel PMU event] ... nmem1/mem_life/ [Kernel PMU event] nmem1/poweron_secs/ [Kernel PMU event] Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Signed-off-by: Kajol Jain <kjain@linux.ibm.com> [Add numa_map_to_online_node function call to get online node id] Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com> Reviewed-by: Madhavan Srinivasan <maddy@in.ibm.com> Link: https://lore.kernel.org/r/20220225143024.47947-4-kjain@linux.ibm.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-03-09powerpc/64: Add UADDR64 relocation supportAlexey Kardashevskiy
When ld detects unaligned relocations, it emits R_PPC64_UADDR64 relocations instead of R_PPC64_RELATIVE. Currently R_PPC64_UADDR64 are detected by arch/powerpc/tools/relocs_check.sh and expected not to work. Below is a simple chunk to trigger this behaviour (this disables optimization for the demonstration purposes only, this also happens with -O1/-O2 when CONFIG_PRINTK_INDEX=y, for example): \#pragma GCC push_options \#pragma GCC optimize ("O0") struct entry { const char *file; int line; } __attribute__((packed)); static const struct entry e1 = { .file = __FILE__, .line = __LINE__ }; static const struct entry e2 = { .file = __FILE__, .line = __LINE__ }; ... prom_printf("e1=%s %lx %lx\n", e1.file, (unsigned long) e1.file, mfmsr()); prom_printf("e2=%s %lx\n", e2.file, (unsigned long) e2.file); \#pragma GCC pop_options This adds support for UADDR64 for 64bit. This reuses __dynamic_symtab from the 32bit code which supports more relocation types already. Because RELACOUNT includes only R_PPC64_RELATIVE, this replaces it with RELASZ which is the size of all relocation records. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220309061822.168173-1-aik@ozlabs.ru
2022-03-09powerpc: 8xx: fix a return value error in mpc8xx_pic_initHangyu Hua
mpc8xx_pic_init() should return -ENOMEM instead of 0 when irq_domain_add_linear() return NULL. This cause mpc8xx_pics_init to continue executing even if mpc8xx_pic_host is NULL. Fixes: cc76404feaed ("powerpc/8xx: Fix possible device node reference leak") Signed-off-by: Hangyu Hua <hbh25y@gmail.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220223070223.26845-1-hbh25y@gmail.com
2022-03-09powerpc/ps3: remove unneeded semicolonsjing yangyang
Eliminate the following coccicheck warnings: ./arch/powerpc/platforms/ps3/system-bus.c:606:2-3: Unneeded semicolon ./arch/powerpc/platforms/ps3/system-bus.c:765:2-3: Unneeded semicolon Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: jing yangyang <jing.yangyang@zte.com.cn> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/01647102607ce9640c9f27786d976109a3c4ea7e.1629197153.git.jing.yangyang@zte.com.cn
2022-03-08KVM: use __vcalloc for very large allocationsPaolo Bonzini
Allocations whose size is related to the memslot size can be arbitrarily large. Do not use kvzalloc/kvcalloc, as those are limited to "not crazy" sizes that fit in 32 bits. Cc: stable@vger.kernel.org Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls") Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-08powerpc/64: Force inlining of prevent_user_access() and set_kuap()Christophe Leroy
A ppc64_defconfig build exhibits about 10 copied of prevent_user_access(). It also have one copy of set_kuap(). c000000000017340 <.prevent_user_access.constprop.0>: c00000000001a038: 4b ff d3 09 bl c000000000017340 <.prevent_user_access.constprop.0> c00000000001aabc: 4b ff c8 85 bl c000000000017340 <.prevent_user_access.constprop.0> c00000000001ab38: 4b ff c8 09 bl c000000000017340 <.prevent_user_access.constprop.0> c00000000001ade0: 4b ff c5 61 bl c000000000017340 <.prevent_user_access.constprop.0> c000000000039b90 <.prevent_user_access.constprop.0>: c00000000003ac08: 4b ff ef 89 bl c000000000039b90 <.prevent_user_access.constprop.0> c00000000003b9d0: 4b ff e1 c1 bl c000000000039b90 <.prevent_user_access.constprop.0> c00000000003ba54: 4b ff e1 3d bl c000000000039b90 <.prevent_user_access.constprop.0> c00000000003bbfc: 4b ff df 95 bl c000000000039b90 <.prevent_user_access.constprop.0> c00000000015dde0 <.prevent_user_access.constprop.0>: c0000000001612c0: 4b ff cb 21 bl c00000000015dde0 <.prevent_user_access.constprop.0> c000000000161b54: 4b ff c2 8d bl c00000000015dde0 <.prevent_user_access.constprop.0> c000000000188cf0 <.prevent_user_access.constprop.0>: c00000000018d658: 4b ff b6 99 bl c000000000188cf0 <.prevent_user_access.constprop.0> c00000000030fe20 <.prevent_user_access.constprop.0>: c0000000003123d4: 4b ff da 4d bl c00000000030fe20 <.prevent_user_access.constprop.0> c000000000313970: 4b ff c4 b1 bl c00000000030fe20 <.prevent_user_access.constprop.0> c0000000005e6bd0 <.prevent_user_access.constprop.0>: c0000000005e7d8c: 4b ff ee 45 bl c0000000005e6bd0 <.prevent_user_access.constprop.0> c0000000007bcae0 <.prevent_user_access.constprop.0>: c0000000007bda10: 4b ff f0 d1 bl c0000000007bcae0 <.prevent_user_access.constprop.0> c0000000007bda54: 4b ff f0 8d bl c0000000007bcae0 <.prevent_user_access.constprop.0> c0000000007bdd28: 4b ff ed b9 bl c0000000007bcae0 <.prevent_user_access.constprop.0> c0000000007c0390: 4b ff c7 51 bl c0000000007bcae0 <.prevent_user_access.constprop.0> c00000000094e4f0 <.prevent_user_access.constprop.0>: c000000000950e40: 4b ff d6 b1 bl c00000000094e4f0 <.prevent_user_access.constprop.0> c00000000097d2d0 <.prevent_user_access.constprop.0>: c0000000009813fc: 4b ff be d5 bl c00000000097d2d0 <.prevent_user_access.constprop.0> c000000000acd540 <.prevent_user_access.constprop.0>: c000000000ad1d60: 4b ff b7 e1 bl c000000000acd540 <.prevent_user_access.constprop.0> c000000000e5d680 <.prevent_user_access.constprop.0>: c000000000e64b60: 4b ff 8b 21 bl c000000000e5d680 <.prevent_user_access.constprop.0> c000000000e64b6c: 4b ff 8b 15 bl c000000000e5d680 <.prevent_user_access.constprop.0> c000000000e64c38: 4b ff 8a 49 bl c000000000e5d680 <.prevent_user_access.constprop.0> When building signal_64.c with -Winline the following messages appear: ./arch/powerpc/include/asm/book3s/64/kup.h:331:20: error: inlining failed in call to 'set_kuap': call is unlikely and code size would grow [-Werror=inline] ./arch/powerpc/include/asm/book3s/64/kup.h:401:20: error: inlining failed in call to 'prevent_user_access.constprop': call is unlikely and code size would grow [-Werror=inline] Those functions are used on hot pathes and have been expected to be inlined at all time. Force them inline. This patch reduces the kernel text size by 700 bytes, confirming that not inlining those functions is not worth it. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/eff9b2b211957fa2e8707e46f31674097fd563a3.1644588972.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/bitops: Force inlining of fls()Christophe Leroy
Building a kernel with CONFIG_CC_OPTIMISE_FOR_SIZE leads to the following functions being copied several times in vmlinux: 31 times __ilog2_u32() 34 times fls() Disassembly follows: c00f476c <fls>: c00f476c: 7c 63 00 34 cntlzw r3,r3 c00f4770: 20 63 00 20 subfic r3,r3,32 c00f4774: 4e 80 00 20 blr c00f4778 <__ilog2_u32>: c00f4778: 94 21 ff f0 stwu r1,-16(r1) c00f477c: 7c 08 02 a6 mflr r0 c00f4780: 90 01 00 14 stw r0,20(r1) c00f4784: 4b ff ff e9 bl c00f476c <fls> c00f4788: 80 01 00 14 lwz r0,20(r1) c00f478c: 38 63 ff ff addi r3,r3,-1 c00f4790: 7c 08 03 a6 mtlr r0 c00f4794: 38 21 00 10 addi r1,r1,16 c00f4798: 4e 80 00 20 blr When forcing inlining of fls(), we get c0008b80 <__ilog2_u32>: c0008b80: 7c 63 00 34 cntlzw r3,r3 c0008b84: 20 63 00 1f subfic r3,r3,31 c0008b88: 4e 80 00 20 blr vmlinux size gets reduced by 1 kbyte with that change. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/adc9c9d6378f6b5008246ca717993d7870188efb.1644569473.git.christophe.leroy@csgroup.eu
2022-03-08powerpc: declare unmodified attribute_group usages constRohan McLure
Inspired by (bd75b4ef4977: Constify static attribute_group structs), accepted by linux-next, reported: https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20220210202805.7750-4-rikard.falkeborn@gmail.com/ Nearly all singletons of type struct attribute_group are never modified, and so are candidates for being const. Declare them as const. Signed-off-by: Rohan McLure <rmclure@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220307231414.86560-1-rmclure@linux.ibm.com
2022-03-08powerpc/spufs: Fix build warning when CONFIG_PROC_FS=nYueHaibing
arch/powerpc/platforms/cell/spufs/sched.c:1055:12: warning: ‘show_spu_loadavg’ defined but not used [-Wunused-function] static int show_spu_loadavg(struct seq_file *s, void *private) ^~~~~~~~~~~~~~~~ Move it into #ifdef block to fix this, also remove unneeded semicolon. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220308100928.23540-1-yuehaibing@huawei.com
2022-03-08powerpc/secvar: fix refcount leak in format_show()Hangyu Hua
Refcount leak will happen when format_show returns failure in multiple cases. Unified management of of_node_put can fix this problem. Signed-off-by: Hangyu Hua <hbh25y@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220302021959.10959-1-hbh25y@gmail.com
2022-03-08powerpc/64e: Tie PPC_BOOK3E_64 to PPC_FSL_BOOK3EMichael Ellerman
Since the IBM A2 CPU support was removed, see commit fb5a515704d7 ("powerpc: Remove platforms/wsp and associated pieces"), the only 64-bit Book3E CPUs we support are Freescale (NXP) ones. However our Kconfig still allows configurating a kernel that has 64-bit Book3E support, but no Freescale CPU support enabled. Such a kernel would never boot, it doesn't know about any CPUs. It also causes build errors, as reported by lkp, because PPC_BARRIER_NOSPEC is not enabled in such a configuration: powerpc64-linux-ld: arch/powerpc/net/bpf_jit_comp64.o:(.toc+0x0): undefined reference to `powerpc_security_features' To fix this, force PPC_FSL_BOOK3E to be selected whenever we are building a 64-bit Book3E kernel. Reported-by: kernel test robot <lkp@intel.com> Reported-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220304061222.2478720-1-mpe@ellerman.id.au
2022-03-08powerpc: Move C prototypes out of asm-prototypes.hChristophe Leroy
We originally added asm-prototypes.h in commit 42f5b4cacd78 ("powerpc: Introduce asm-prototypes.h"). It's purpose was for prototypes of C functions that are only called from asm, in order to fix sparse warnings about missing prototypes. A few months later Nick added a different use case in commit 4efca4ed05cb ("kbuild: modversions for EXPORT_SYMBOL() for asm") for C prototypes for exported asm functions. This is basically the inverse of our original usage. Since then we've added various prototypes to asm-prototypes.h for both reasons, meaning we now need to unstitch it all. Dispatch prototypes of C functions into relevant headers and keep only the prototypes for functions defined in assembly. For the time being, leave prom_init() there because moving it into asm/prom.h or asm/setup.h conflicts with drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowrom.o This will be fixed later by untaggling asm/pci.h and asm/prom.h or by renaming the function in shadowrom.c Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/62d46904eca74042097acf4cb12c175e3067f3d1.1646413435.git.christophe.leroy@csgroup.eu
2022-03-08KVM: PPC: Use KVM_CAP_PPC_AIL_MODE_3Nicholas Piggin
Use KVM_CAP_PPC_AIL_MODE_3 to advertise the capability to set the AIL resource mode to 3 with the H_SET_MODE hypercall. This capability differs between processor types and KVM types (PR, HV, Nested HV), and affects guest-visible behaviour. QEMU will implement a cap-ail-mode-3 to control this behaviour[1], and use the KVM CAP if available to determine KVM support[2]. [1] https://lists.nongnu.org/archive/html/qemu-ppc/2022-02/msg00437.html [2] https://lists.nongnu.org/archive/html/qemu-ppc/2022-02/msg00439.html Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> [mpe: Rebase onto 93b71801a827 from kvm-ppc-cap-210 branch, add EXPORT_SYMBOL] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220222064727.2314380-4-npiggin@gmail.com
2022-03-08KVM: PPC: Book3S PR: Disallow AIL != 0Nicholas Piggin
KVM PR does not implement address translation modes on interrupt, so it must not allow H_SET_MODE to succeed. The behaviour change caused by this mode is architected and not advisory (interrupts *must* behave differently). QEMU does not deal with differences in AIL support in the host. The solution to that is a spapr capability and corresponding KVM CAP, but this patch does not break things more than before (the host behaviour already differs, this change just disallows some modes that are not implemented properly). By happy coincidence, this allows PR Linux guests that are using the SCV facility to boot and run, because Linux disables the use of SCV if AIL can not be set to 3. This does not fix the underlying problem of missing SCV support (an OS could implement real-mode SCV vectors and try to enable the facility). The true fix for that is for KVM PR to emulate scv interrupts from the facility unavailable interrupt. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Link: https://lore.kernel.org/r/20220222064727.2314380-3-npiggin@gmail.com
2022-03-08KVM: PPC: Book3S PR: Disable SCV when AIL could be disabledNicholas Piggin
PR KVM does not support running with AIL enabled, and SCV does is not supported with AIL disabled. Fix this by ensuring the SCV facility is disabled with FSCR while a CPU could be running with AIL=0. The PowerNV host supports disabling AIL on a per-CPU basis, so SCV just needs to be disabled when a vCPU is being run. The pSeries machine can only switch AIL on a system-wide basis, so it must disable SCV support at boot if the configuration can potentially run a PR KVM guest. Also ensure a the FSCR[SCV] bit can not be enabled when emulating mtFSCR for the guest. SCV is not emulated for the PR guest at the moment, this just fixes the host crashes. Alternatives considered and rejected: - SCV support can not be disabled by PR KVM after boot, because it is advertised to userspace with HWCAP. - AIL can not be disabled on a per-CPU basis. At least when running on pseries it is a per-LPAR setting. - Support for real-mode SCV vectors will not be added because they are at 0x17000 so making such a large fixed head space causes immediate value limits to be exceeded, requiring a lot rework and more code. - Disabling SCV for any PR KVM possible kernel will cause a slowdown when not using PR KVM. - A boot time option to disable SCV to use PR KVM is user-hostile. - System call instruction emulation for SCV facility unavailable instructions is too complex and old emulation code was subtly broken and removed. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Link: https://lore.kernel.org/r/20220222064727.2314380-2-npiggin@gmail.com
2022-03-08powerpc/kexec: Declare kexec_paca staticChristophe Leroy
kexec_paca is exclusively used in kexec/core_64.c Declare it static. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/094983ee851644165b7700c73cac63cfe20596cd.1646413435.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/smp: Declare current_set staticChristophe Leroy
current_set extern not needed anymore since commit eafd825ed710 ("powerpc/64: Simplify __secondary_start paca->kstack handling") Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a55eb65c9d7319f0af3c31e3f6ba36522f10003d.1646413435.git.christophe.leroy@csgroup.eu
2022-03-08powerpc: Cleanup asm-prototypes.cChristophe Leroy
Last call to sys_swapcontext() from ASM was removed by commit fbcee2ebe8ed ("powerpc/32: Always save non volatile GPRs at syscall entry") sys_debug_setcontext() prototype not needed anymore since commit f3675644e172 ("powerpc/syscalls: signal_{32, 64} - switch to SYSCALL_DEFINE") sys_switch_endian() prototype not needed anymore since commit 81dac8177862 ("powerpc/64: Make sys_switch_endian() traceable") Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> [mpe: Keep _mcount() prototype to avoid modpost errors] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/3ed660a585df2080ea8412ec20fbf652f5bf013a.1646413435.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/ftrace: Use STK_GOT in ftrace_mprofile.SChristophe Leroy
Instead of open coding offset value 24, use STK_GOT when accessing got register in stack. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9042bb30fa972056715fe5b6598a7c8049681293.1645099283.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.SChristophe Leroy
CONFIG_MPROFILE_KERNEL is only for PPC64 and ftrace_mprofile.o is build on PPC64 only when CONFIG_MPROFILE_KERNEL is defined. Move saving of r0 inside #ifdef PPC64 Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/619dfb672bf4f1b777a4b3f8b4f14e637fea2716.1645099283.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/ftrace: Refactor ftrace_{regs_}callerChristophe Leroy
ftrace_caller() and frace_regs_caller() have now a lot in common. Refactor them using GAS macros. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/9d7df9e4fc98a86051489f61d3c9bc67f92f7e27.1645099283.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/ftrace: Don't use lmw/stmw in ftrace_regs_caller()Christophe Leroy
For the same reason as commit a85c728cb5e1 ("powerpc/32: Don't use lmw/stmw for saving/restoring non volatile regs"), don't use lmw/stmw in ftrace_regs_caller(). Use the same macros for PPC32 and PPC64. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/ec286d2cc6989668a96f14543275437d2f3f0e3a.1645099283.git.christophe.leroy@csgroup.eu
2022-03-08powerpc/pseries: Interface to represent PAPR firmware attributesPratik R. Sampat
Adds a syscall interface to represent the energy and frequency related PAPR attributes on the system using the new H_CALL "H_GET_ENERGY_SCALE_INFO". H_GET_EM_PARMS H_CALL was previously responsible for exporting this information in the lparcfg, however the H_GET_EM_PARMS H_CALL will be deprecated P10 onwards. The H_GET_ENERGY_SCALE_INFO H_CALL is of the following call format: hcall( uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info uint64 flags, // Per the flag request uint64 firstAttributeId,// The attribute id uint64 bufferAddress, // Guest physical address of the output buffer uint64 bufferSize // The size in bytes of the output buffer ); As specified in PAPR+ v2.11, section 14.14.3. This H_CALL can query either all the attributes at once with firstAttributeId = 0, flags = 0 as well as query only one attribute at a time with firstAttributeId = id, flags = 1. The output buffer consists of the following 1. number of attributes - 8 bytes 2. array offset to the data location - 8 bytes 3. version info - 1 byte 4. A data array of size num attributes, which contains the following: a. attribute ID - 8 bytes b. attribute value in number - 8 bytes c. attribute name in string - 64 bytes d. attribute value in string - 64 bytes The new H_CALL exports information in direct string value format, hence a new interface has been introduced in /sys/firmware/papr/energy_scale_info to export this information to userspace so that the firmware can add new values without the need for the kernel to be changed. The H_CALL returns the name, numeric value and string value (if exists) The format of exposing the sysfs information is as follows: /sys/firmware/papr/energy_scale_info/ |-- <id>/ |-- desc |-- value |-- value_desc (if exists) |-- <id>/ |-- desc |-- value |-- value_desc (if exists) ... The energy information that is exported is useful for userspace tools such as powerpc-utils. Currently these tools infer the "power_mode_data" value in the lparcfg, which in turn is obtained from the to be deprecated H_GET_EM_PARMS H_CALL. On future platforms, such userspace utilities will have to look at the data returned from the new H_CALL being populated in this new sysfs interface and report this information directly without the need of interpretation. Signed-off-by: Pratik R. Sampat <psampat@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220217105321.52941-2-psampat@linux.ibm.com
2022-03-08powerpc/mce: Avoid using irq_work_queue() in realmodeGanesh Goudar
In realmode mce handler we use irq_work_queue() to defer the processing of mce events, irq_work_queue() can only be called when translation is enabled because it touches memory outside RMA, hence we enable translation before calling irq_work_queue and disable on return, though it is not safe to do in realmode. To avoid this, program the decrementer and call the event processing functions from timer handler. Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com
2022-03-08powerpc/mce: Modify the real address error logging messagesGanesh Goudar
To avoid ambiguity, modify the strings in real address error logging messages to "foreign/control memory" from "foreign", Since the error discriptions in P9 user manual and P10 user manual are different for same type of errors. P9 User Manual for MCE: DSISR:59 Host real address to foreign space during translation. DSISR:60 Host real address to foreign space on a load or store access. P10 User Manual for MCE: DSISR:59 D-side tablewalk used a host real address in the control memory address range. DSISR:60 D-side operand access to control memory address space. Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220107141428.67862-3-ganeshgr@linux.ibm.com
2022-03-08powerpc/pseries: Parse control memory access errorGanesh Goudar
Add support to parse and log control memory access error for pseries. These changes are made according to PAPR v2.11 10.3.2.2.12. Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220107141428.67862-1-ganeshgr@linux.ibm.com
2022-03-08powerpc/bpf: Simplify bpf_to_ppc() and adopt it for powerpc64Naveen N. Rao
Convert bpf_to_ppc() to a macro to help simplify its usage since codegen_context is available in all places it is used. Adopt it also for powerpc64 for uniformity and get rid of the global b2p structure. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/09f0540ce3e0cd4120b5b33993b5e73b6ef9e979.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc64/bpf: Store temp registers' bpf to ppc mappingJordan Niethe
In bpf_jit_build_body(), the mapping of TMP_REG_1 and TMP_REG_2's bpf register to ppc register is evalulated at every use despite not changing. Instead, determine the ppc register once and store the result. Signed-off-by: Jordan Niethe <jniethe5@gmail.com> [Rebased, converted additional usage sites] Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/0944e2f0fa6dd254ea401f1c946fb6c9a5294278.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc/bpf: Use _Rn macros for GPRsNaveen N. Rao
Use _Rn macros to specify register names to make their usage clear. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/7df626b8cdc6141d4295ac16137c82ad570b6637.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc/bpf: Move bpf_jit64.h into bpf_jit_comp64.cNaveen N. Rao
There is no need for a separate header anymore. Move the contents of bpf_jit64.h into bpf_jit_comp64.c Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/b873a8e6eff7d91bf2a2cabdd53082aadfe20761.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc/bpf: Cleanup bpf_jit.hNaveen N. Rao
- PPC_EX32() is only used by ppc32 JIT. Move it to bpf_jit_comp32.c - PPC_LI64() is only valid in ppc64. #ifdef it - PPC_FUNC_ADDR() is not used anymore. Remove it. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/58f5b66b2f8546bbbee620f62103a8e97a63eb7c.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc64/bpf: Get rid of PPC_BPF_[LL|STL|STLU] macrosNaveen N. Rao
All these macros now have a single user. Expand their usage in place. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/e0526fc7633a34f983a7a330712b55bdfaf20482.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc64/bpf: Convert some of the uses of PPC_BPF_[LL|STL] to PPC_BPF_[LD|STD]Naveen N. Rao
PPC_BPF_[LL|STL] are macros meant for scenarios where we may have to deal with a non-word aligned offset. Limit their usage to only those scenarios by converting the rest to just use PPC_BPF_[LD|STD]. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/0eb472428165a307f6fdaf22b0c33cbf13a9a635.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc/bpf: Rename PPC_BL_ABS() to PPC_BL()Naveen N. Rao
PPC_BL_ABS() is just doing a relative branch with link. The name suggests that it is for branching to an absolute address, which is incorrect. Rename the macro to a more appropriate PPC_BL(). Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/f0e57b6c7a6ee40dba645535b70da46f46e8af5e.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc64/bpf: Optimize instruction sequence used for function callsNaveen N. Rao
When calling BPF helpers, we load the function address to call into a register. This can result in upto 5 instructions. Optimize this by instead using the kernel toc in r2 and adjusting offset to the BPF helper. This works since all BPF helpers are part of kernel text, and all BPF programs/functions utilize the kernel TOC. Further more: - load the actual function entry address in elf v1, rather than loading it through the function descriptor address. - load the Local Entry Point (LEP) in elf v2 skipping TOC setup. - consolidate code across elf abi v1 and v2 by using r12 on both. Reported-by: Anton Blanchard <anton@ozlabs.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1233c7544e60dcb021c52b1f840b0f21a87b33ed.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc64/bpf elfv1: Do not load TOC before calling functionsNaveen N. Rao
BPF helpers always reside in core kernel and all BPF programs use the kernel TOC. As such, there is no need to load the TOC before calling helpers or other BPF functions. Drop code to do the same. Add a check to ensure we don't proceed if this assumption ever changes in future. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a3cd3da4d24d95d845cd10382b1af083600c9074.1644834730.git.naveen.n.rao@linux.vnet.ibm.com
2022-03-08powerpc64/bpf elfv2: Setup kernel TOC in r2 on entryNaveen N. Rao
In preparation for using kernel TOC, load the same in r2 on entry. With elfv1, the kernel TOC is already setup by our caller. We adjust the number of instructions to skip on a tail call accordingly. We get rid of the #ifdef in bpf_jit_emit_tail_call() since FUNCTION_DESCR_SIZE is itself under a #ifdef. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/18a05a4ceec14a8617c9dd4b7128d0afa83fd14e.1644834730.git.naveen.n.rao@linux.vnet.ibm.com