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 | |
| 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')
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 18 | ||||
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 25 |
2 files changed, 32 insertions, 11 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 99c908226065..54c10503d71f 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -241,9 +241,7 @@ local_restart: tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls? bne __sys_trace - cmp scno, #NR_syscalls @ check upper syscall limit - badr lr, ret_fast_syscall @ return address - ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine + invoke_syscall tbl, scno, r10, ret_fast_syscall add r1, sp, #S_OFF 2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) @@ -277,14 +275,8 @@ __sys_trace: mov r1, scno add r0, sp, #S_OFF bl syscall_trace_enter - - badr lr, __sys_trace_return @ return address - mov scno, r0 @ syscall number (possibly new) - add r1, sp, #S_R0 + S_OFF @ pointer to regs - cmp scno, #NR_syscalls @ check upper syscall limit - ldmccia r1, {r0 - r6} @ have to reload r0 - r6 - stmccia sp, {r4, r5} @ and update the stack args - ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine + mov scno, r0 + invoke_syscall tbl, scno, r10, __sys_trace_return, reload=1 cmp scno, #-1 @ skip the syscall? bne 2b add sp, sp, #S_OFF @ restore stack @@ -362,6 +354,10 @@ sys_syscall: bic scno, r0, #__NR_OABI_SYSCALL_BASE cmp scno, #__NR_syscall - __NR_SYSCALL_BASE cmpne scno, #NR_syscalls @ check range +#ifdef CONFIG_CPU_SPECTRE + movhs scno, #0 + csdb +#endif stmloia sp, {r5, r6} @ shuffle args movlo r0, r1 movlo r1, r2 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. |