Messages in this thread Patch in this message | | | Date | Tue, 13 Feb 2018 12:21:18 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 2/2] x86/retpoline: Fix return buffer filling |
| |
On Mon, Feb 12, 2018 at 04:04:22PM -0800, Andi Kleen wrote: > From: Andi Kleen <ak@linux.intel.com> > > An earlier patch moved the RSB filling out of line, ending > it with a return. This results in the return buffer filling > only giving 15 instead of 16 usable returns because > the return from fill_rsb already uses one up.
Or, we can get rid of the RET:
--- diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index 480edc3a5e03..359130ceaa64 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -91,7 +91,8 @@ GENERATE_THUNK(r15) ENTRY(__fill_rsb) STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP - ret + pop %_ASM_BX + jmp *%_ASM_BX END(__fill_rsb) EXPORT_SYMBOL_GPL(__fill_rsb) @@ -99,6 +100,7 @@ EXPORT_SYMBOL_GPL(__fill_rsb) ENTRY(__clear_rsb) STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP - ret + pop %_ASM_BX + jmp *%_ASM_BX END(__clear_rsb) EXPORT_SYMBOL_GPL(__clear_rsb) -- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
| |