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| author |   Michael Ellerman <mpe@ellerman.id.au> | 2018-04-24 14:15:59 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-06-03 20:43:45 +1000 |
| commit | 51973a815c6b46d7b23b68d6af371ad1c9d503ca (patch) | |
| tree | dd5bd1a449e91b922db6afb4c097eca2cea01583 | |
| parent | powerpc: Use barrier_nospec in copy_from_user() (diff) | |
| download | linux-dev-51973a815c6b46d7b23b68d6af371ad1c9d503ca.tar.xz linux-dev-51973a815c6b46d7b23b68d6af371ad1c9d503ca.zip | |
powerpc/64: Use barrier_nospec in syscall entry
Our syscall entry is done in assembly so patch in an explicit
barrier_nospec.
Based on a patch by Michal Suchanek.
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 3d1af55e09dc..b10e01021214 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -36,6 +36,7 @@ #include <asm/context_tracking.h> #include <asm/tm.h> #include <asm/ppc-opcode.h> +#include <asm/barrier.h> #include <asm/export.h> #ifdef CONFIG_PPC_BOOK3S #include <asm/exception-64s.h> @@ -178,6 +179,15 @@ system_call: /* label this so stack traces look sane */ clrldi r8,r8,32 15: slwi r0,r0,4 + + barrier_nospec_asm + /* + * Prevent the load of the handler below (based on the user-passed + * system call number) being speculatively executed until the test + * against NR_syscalls and branch to .Lsyscall_enosys above has + * committed. + */ + ldx r12,r11,r0 /* Fetch system call handler [ptr] */ mtctr r12 bctrl /* Call handler */ |