diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2019-04-22 00:20:14 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 19:44:48 +0200 |
| commit | 2a90ebba2fccef2853063fe7412c20dacc5af7e7 (patch) | |
| tree | cf6c5d227710e36624d6937f06f700a89cc58aeb | |
| parent | 990ce72a3babcf376e1132f157b1a19f7c43681e (diff) | |
powerpc/64: Use barrier_nospec in syscall entry
commit 51973a815c6b46d7b23b68d6af371ad1c9d503ca upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 59be96917369..9c2e58e0e55e 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -36,6 +36,7 @@ #include <asm/hw_irq.h> #include <asm/context_tracking.h> #include <asm/tm.h> +#include <asm/barrier.h> #ifdef CONFIG_PPC_BOOK3S #include <asm/exception-64s.h> #else @@ -177,6 +178,15 @@ 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 */ |