diff options
| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2020-01-31 11:34:54 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-02-19 22:46:08 +1100 |
| commit | 9e27086292aa880921a0f2b8501e5189d5efcf03 (patch) | |
| tree | 79b9c6c21074e5da094dce9cf912ad3b7bd313b3 /arch/powerpc/kernel/head_32.h | |
| parent | 030e347430957f6f7f29db9099368f8b86c0bf76 (diff) | |
powerpc/32: Warn and return ENOSYS on syscalls from kernel
Since commit b86fb88855ea ("powerpc/32: implement fast entry for
syscalls on non BOOKE") and commit 1a4b739bbb4f ("powerpc/32:
implement fast entry for syscalls on BOOKE"), syscalls from
kernel are unexpected and can have catastrophic consequences
as it will destroy the kernel stack.
Test MSR_PR on syscall entry. In case syscall is from kernel,
emit a warning and return ENOSYS error.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8ee3bdbbdfdfc64ca7001e90c43b2aee6f333578.1580470482.git.christophe.leroy@c-s.fr
Diffstat (limited to 'arch/powerpc/kernel/head_32.h')
| -rw-r--r-- | arch/powerpc/kernel/head_32.h | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index a6a5fbbf8504..0e7bf28fe53a 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -111,14 +111,16 @@ .macro SYSCALL_ENTRY trapno mfspr r12,SPRN_SPRG_THREAD + mfspr r9, SPRN_SRR1 #ifdef CONFIG_VMAP_STACK - mfspr r9, SPRN_SRR0 - mfspr r11, SPRN_SRR1 - stw r9, SRR0(r12) - stw r11, SRR1(r12) + mfspr r11, SPRN_SRR0 + stw r11, SRR0(r12) + stw r9, SRR1(r12) #endif mfcr r10 + andi. r11, r9, MSR_PR lwz r11,TASK_STACK-THREAD(r12) + beq- 99f rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */ addi r11, r11, THREAD_SIZE - INT_FRAME_SIZE #ifdef CONFIG_VMAP_STACK @@ -128,15 +130,14 @@ #endif tovirt_vmstack r12, r12 tophys_novmstack r11, r11 - mflr r9 stw r10,_CCR(r11) /* save registers */ - stw r9, _LINK(r11) + mflr r10 + stw r10, _LINK(r11) #ifdef CONFIG_VMAP_STACK lwz r10, SRR0(r12) lwz r9, SRR1(r12) #else mfspr r10,SPRN_SRR0 - mfspr r9,SPRN_SRR1 #endif stw r1,GPR1(r11) stw r1,0(r11) @@ -209,6 +210,7 @@ mtspr SPRN_SRR0,r11 SYNC RFI /* jump to handler, enable MMU */ +99: b ret_from_kernel_syscall .endm .macro save_dar_dsisr_on_stack reg1, reg2, sp |