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| author | Thomas Gleixner <tglx@linutronix.de> | 2022-09-15 13:11:34 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-10-17 16:41:18 +0200 |
| commit | b2e9dfe54be4d023124d588d6f03d16a9c0d2507 (patch) | |
| tree | 8f1e2c50ab4cd7cec00b3dff8764e2f2e6dbb035 /arch/x86/kernel | |
| parent | x86/orc: Make it callthunk aware (diff) | |
| download | linux-b2e9dfe54be4d023124d588d6f03d16a9c0d2507.tar.xz linux-b2e9dfe54be4d023124d588d6f03d16a9c0d2507.zip | |
x86/bpf: Emit call depth accounting if required
Ensure that calls in BPF jitted programs are emitting call depth accounting
when enabled to keep the call/return balanced. The return thunk jump is
already injected due to the earlier retbleed mitigations.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.615413406@infradead.org
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/callthunks.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c index 7f9788194eb5..a03d646b5e69 100644 --- a/arch/x86/kernel/callthunks.c +++ b/arch/x86/kernel/callthunks.c @@ -306,6 +306,25 @@ bool is_callthunk(void *addr) return !bcmp((void *)(dest - tmpl_size), tmpl, tmpl_size); } +#ifdef CONFIG_BPF_JIT +int x86_call_depth_emit_accounting(u8 **pprog, void *func) +{ + unsigned int tmpl_size = SKL_TMPL_SIZE; + void *tmpl = skl_call_thunk_template; + + if (!thunks_initialized) + return 0; + + /* Is function call target a thunk? */ + if (is_callthunk(func)) + return 0; + + memcpy(*pprog, tmpl, tmpl_size); + *pprog += tmpl_size; + return tmpl_size; +} +#endif + #ifdef CONFIG_MODULES void noinline callthunks_patch_module_calls(struct callthunk_sites *cs, struct module *mod) |