diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-11 11:16:22 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-31 23:27:26 +0100 |
| commit | 10573ae547c85b2c61417ff1a106cffbfceada35 (patch) | |
| tree | dbc21a6b8a94eaa26fdc73b4440affa5ad082e4c /arch/arm/kernel/entry-header.S | |
| parent | 1d4238c56f9816ce0f9c8dbe42d7f2ad81cb6613 (diff) | |
ARM: spectre-v1: fix syscall entry
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>
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. |