Messages in this thread Patch in this message | | | Date | Fri, 02 Sep 2022 15:07:15 +0200 | From | Peter Zijlstra <> | Subject | [PATCH v2 50/59] x86/retbleed: Add SKL call thunk |
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From: Thomas Gleixner <tglx@linutronix.de>
Add the actual SKL call thunk for call depth accounting.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/x86/kernel/callthunks.c | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
--- a/arch/x86/kernel/callthunks.c +++ b/arch/x86/kernel/callthunks.c @@ -7,6 +7,7 @@ #include <linux/moduleloader.h> #include <asm/alternative.h> +#include <asm/asm-offsets.h> #include <asm/cpu.h> #include <asm/ftrace.h> #include <asm/insn.h> @@ -55,7 +56,21 @@ static const struct core_text builtin_co .name = "builtin", }; -static struct thunk_desc callthunk_desc __ro_after_init; +asm ( + ".pushsection .rodata \n" + ".global skl_call_thunk_template \n" + "skl_call_thunk_template: \n" + __stringify(INCREMENT_CALL_DEPTH)" \n" + ".global skl_call_thunk_tail \n" + "skl_call_thunk_tail: \n" + ".popsection \n" +); + +extern u8 skl_call_thunk_template[]; +extern u8 skl_call_thunk_tail[]; + +#define SKL_TMPL_SIZE \ + ((unsigned int)(skl_call_thunk_tail - skl_call_thunk_template)) extern void error_entry(void); extern void xen_error_entry(void); @@ -157,11 +172,11 @@ static const u8 nops[] = { static __init_or_module void *patch_dest(void *dest, bool direct) { - unsigned int tsize = callthunk_desc.template_size; + unsigned int tsize = SKL_TMPL_SIZE; u8 *pad = dest - tsize; /* Already patched? */ - if (!bcmp(pad, callthunk_desc.template, tsize)) + if (!bcmp(pad, skl_call_thunk_template, tsize)) return pad; /* Ensure there are nops */ @@ -171,9 +186,9 @@ static __init_or_module void *patch_dest } if (direct) - memcpy(pad, callthunk_desc.template, tsize); + memcpy(pad, skl_call_thunk_template, tsize); else - text_poke_copy_locked(pad, callthunk_desc.template, tsize, true); + text_poke_copy_locked(pad, skl_call_thunk_template, tsize, true); return pad; }
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