x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n
commit b2620facef4889fefcbf2e87284f34dcd4189bce upstream. If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be silently disabled. There's nothing retpoline-specific about RSB buffer filling. Remove the CONFIG_RETPOLINE guards around it. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
9f3330d493
commit
ca47b5c598
@ -643,7 +643,6 @@ ENTRY(__switch_to_asm)
|
||||
movl %ebx, PER_CPU_VAR(stack_canary)+stack_canary_offset
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_RETPOLINE
|
||||
/*
|
||||
* When switching from a shallower to a deeper call stack
|
||||
* the RSB may either underflow or use entries populated
|
||||
@ -652,7 +651,6 @@ ENTRY(__switch_to_asm)
|
||||
* speculative execution to prevent attack.
|
||||
*/
|
||||
FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
|
||||
#endif
|
||||
|
||||
/* restore callee-saved registers */
|
||||
popfl
|
||||
|
@ -367,7 +367,6 @@ ENTRY(__switch_to_asm)
|
||||
movq %rbx, PER_CPU_VAR(irq_stack_union)+stack_canary_offset
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_RETPOLINE
|
||||
/*
|
||||
* When switching from a shallower to a deeper call stack
|
||||
* the RSB may either underflow or use entries populated
|
||||
@ -376,7 +375,6 @@ ENTRY(__switch_to_asm)
|
||||
* speculative execution to prevent attack.
|
||||
*/
|
||||
FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
|
||||
#endif
|
||||
|
||||
/* restore callee-saved registers */
|
||||
popfq
|
||||
|
@ -159,11 +159,9 @@
|
||||
* monstrosity above, manually.
|
||||
*/
|
||||
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
|
||||
#ifdef CONFIG_RETPOLINE
|
||||
ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
|
||||
__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
|
||||
.Lskip_rsb_\@:
|
||||
#endif
|
||||
.endm
|
||||
|
||||
#else /* __ASSEMBLY__ */
|
||||
|
Loading…
Reference in New Issue
Block a user