diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-10-15 11:32:12 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-18 09:16:27 +0200 |
| commit | b690ec0dc735545bca2b78bee639d1545bda97e6 (patch) | |
| tree | cb6e77dc66073faf08ee69426af41f5acd55a870 /arch/arm/kernel/entry-header.S | |
| parent | 4186f7cfa1d6083e969638c8e98b205163da7e2a (diff) | |
ARM: spectre-v1: fix syscall entry
Commit 10573ae547c85b2c61417ff1a106cffbfceada35 upstream.
Prevent speculation at the syscall table decoding by clamping the index
used to zero on invalid system call numbers, and using the csdb
speculative barrier.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm/kernel/entry-header.S')
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 0f07579af472..773424843d6e 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -378,6 +378,31 @@ #endif .endm + .macro invoke_syscall, table, nr, tmp, ret, reload=0 +#ifdef CONFIG_CPU_SPECTRE + mov \tmp, \nr + cmp \tmp, #NR_syscalls @ check upper syscall limit + movcs \tmp, #0 + csdb + badr lr, \ret @ return address + .if \reload + add r1, sp, #S_R0 + S_OFF @ pointer to regs + ldmccia r1, {r0 - r6} @ reload r0-r6 + stmccia sp, {r4, r5} @ update stack arguments + .endif + ldrcc pc, [\table, \tmp, lsl #2] @ call sys_* routine +#else + cmp \nr, #NR_syscalls @ check upper syscall limit + badr lr, \ret @ return address + .if \reload + add r1, sp, #S_R0 + S_OFF @ pointer to regs + ldmccia r1, {r0 - r6} @ reload r0-r6 + stmccia sp, {r4, r5} @ update stack arguments + .endif + ldrcc pc, [\table, \nr, lsl #2] @ call sys_* routine +#endif + .endm + /* * These are the registers used in the syscall handler, and allow us to * have in theory up to 7 arguments to a function - r0 to r6. |