diff options
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 48 |
1 files changed, 41 insertions, 7 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 3d19c830e1b1..f048e384ff54 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -23,7 +23,6 @@ #include <asm/segment.h> #include <asm/cache.h> #include <asm/errno.h> -#include "calling.h" #include <asm/asm-offsets.h> #include <asm/msr.h> #include <asm/unistd.h> @@ -40,6 +39,8 @@ #include <asm/frame.h> #include <linux/err.h> +#include "calling.h" + .code64 .section .entry.text, "ax" @@ -168,6 +169,9 @@ ENTRY(entry_SYSCALL_64_trampoline) /* Stash the user RSP. */ movq %rsp, RSP_SCRATCH + /* Note: using %rsp as a scratch reg. */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp + /* Load the top of the task stack into RSP */ movq CPU_ENTRY_AREA_tss + TSS_sp1 + CPU_ENTRY_AREA, %rsp @@ -207,6 +211,10 @@ ENTRY(entry_SYSCALL_64) */ swapgs + /* + * This path is not taken when PAGE_TABLE_ISOLATION is disabled so it + * is not required to switch CR3. + */ movq %rsp, PER_CPU_VAR(rsp_scratch) movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp @@ -403,6 +411,7 @@ syscall_return_via_sysret: * We are on the trampoline stack. All regs except RDI are live. * We can do future final exit work right here. */ + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi popq %rdi popq %rsp @@ -740,6 +749,8 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode) * We can do future final exit work right here. */ + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi + /* Restore RDI. */ popq %rdi SWAPGS @@ -822,7 +833,9 @@ native_irq_return_ldt: */ pushq %rdi /* Stash user RDI */ - SWAPGS + SWAPGS /* to kernel GS */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi /* to kernel CR3 */ + movq PER_CPU_VAR(espfix_waddr), %rdi movq %rax, (0*8)(%rdi) /* user RAX */ movq (1*8)(%rsp), %rax /* user RIP */ @@ -838,7 +851,6 @@ native_irq_return_ldt: /* Now RAX == RSP. */ andl $0xffff0000, %eax /* RAX = (RSP & 0xffff0000) */ - popq %rdi /* Restore user RDI */ /* * espfix_stack[31:16] == 0. The page tables are set up such that @@ -849,7 +861,11 @@ native_irq_return_ldt: * still points to an RO alias of the ESPFIX stack. */ orq PER_CPU_VAR(espfix_stack), %rax - SWAPGS + + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi + SWAPGS /* to user GS */ + popq %rdi /* Restore user RDI */ + movq %rax, %rsp UNWIND_HINT_IRET_REGS offset=8 @@ -949,6 +965,8 @@ ENTRY(switch_to_thread_stack) UNWIND_HINT_FUNC pushq %rdi + /* Need to switch before accessing the thread stack. */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi movq %rsp, %rdi movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI @@ -1250,7 +1268,11 @@ ENTRY(paranoid_entry) js 1f /* negative -> in kernel */ SWAPGS xorl %ebx, %ebx -1: ret + +1: + SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 + + ret END(paranoid_entry) /* @@ -1272,6 +1294,7 @@ ENTRY(paranoid_exit) testl %ebx, %ebx /* swapgs needed? */ jnz .Lparanoid_exit_no_swapgs TRACE_IRQS_IRETQ + RESTORE_CR3 scratch_reg=%rbx save_reg=%r14 SWAPGS_UNSAFE_STACK jmp .Lparanoid_exit_restore .Lparanoid_exit_no_swapgs: @@ -1299,6 +1322,8 @@ ENTRY(error_entry) * from user mode due to an IRET fault. */ SWAPGS + /* We have user CR3. Change to kernel CR3. */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax .Lerror_entry_from_usermode_after_swapgs: /* Put us onto the real thread stack. */ @@ -1345,6 +1370,7 @@ ENTRY(error_entry) * .Lgs_change's error handler with kernel gsbase. */ SWAPGS + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax jmp .Lerror_entry_done .Lbstep_iret: @@ -1354,10 +1380,11 @@ ENTRY(error_entry) .Lerror_bad_iret: /* - * We came from an IRET to user mode, so we have user gsbase. - * Switch to kernel gsbase: + * We came from an IRET to user mode, so we have user + * gsbase and CR3. Switch to kernel gsbase and CR3: */ SWAPGS + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax /* * Pretend that the exception came from user mode: set up pt_regs @@ -1389,6 +1416,10 @@ END(error_exit) /* * Runs on exception stack. Xen PV does not go through this path at all, * so we can use real assembly here. + * + * Registers: + * %r14: Used to save/restore the CR3 of the interrupted context + * when PAGE_TABLE_ISOLATION is in use. Do not clobber. */ ENTRY(nmi) UNWIND_HINT_IRET_REGS @@ -1452,6 +1483,7 @@ ENTRY(nmi) swapgs cld + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdx movq %rsp, %rdx movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp UNWIND_HINT_IRET_REGS base=%rdx offset=8 @@ -1704,6 +1736,8 @@ end_repeat_nmi: movq $-1, %rsi call do_nmi + RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 + testl %ebx, %ebx /* swapgs needed? */ jnz nmi_restore nmi_swapgs: |