From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: peterz@infradead.org, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com,
jbaron@akamai.com, torvalds@linux-foundation.org,
tglx@linutronix.de, mingo@kernel.org, namit@vmware.com,
hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org,
jpoimboe@redhat.com, pbonzini@redhat.com,
mathieu.desnoyers@efficios.com, linux@rasmusvillemoes.dk
Subject: [PATCH v5 12/17] x86/alternatives: Teach text_poke_bp() to emulate RET
Date: Wed, 24 Jun 2020 17:30:36 +0200 [thread overview]
Message-ID: <20200624154157.449643778@infradead.org> (raw)
In-Reply-To: 20200624153024.794671356@infradead.org
Future patches will need to poke a RET instruction, provide the
infrastructure required for this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/text-patching.h | 19 +++++++++++++++++++
arch/x86/kernel/alternative.c | 5 +++++
2 files changed, 24 insertions(+)
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -53,6 +53,9 @@ extern void text_poke_finish(void);
#define INT3_INSN_SIZE 1
#define INT3_INSN_OPCODE 0xCC
+#define RET_INSN_SIZE 1
+#define RET_INSN_OPCODE 0xC3
+
#define CALL_INSN_SIZE 5
#define CALL_INSN_OPCODE 0xE8
@@ -73,6 +76,7 @@ static __always_inline int text_opcode_s
switch(opcode) {
__CASE(INT3);
+ __CASE(RET);
__CASE(CALL);
__CASE(JMP32);
__CASE(JMP8);
@@ -141,11 +145,26 @@ void int3_emulate_push(struct pt_regs *r
}
static __always_inline
+unsigned long int3_emulate_pop(struct pt_regs *regs)
+{
+ unsigned long val = *(unsigned long *)regs->sp;
+ regs->sp += sizeof(unsigned long);
+ return val;
+}
+
+static __always_inline
void int3_emulate_call(struct pt_regs *regs, unsigned long func)
{
int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
int3_emulate_jmp(regs, func);
}
+
+static __always_inline
+void int3_emulate_ret(struct pt_regs *regs)
+{
+ unsigned long ip = int3_emulate_pop(regs);
+ int3_emulate_jmp(regs, ip);
+}
#endif /* !CONFIG_UML_X86 */
#endif /* _ASM_X86_TEXT_PATCHING_H */
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1099,6 +1099,10 @@ int noinstr poke_int3_handler(struct pt_
*/
goto out_put;
+ case RET_INSN_OPCODE:
+ int3_emulate_ret(regs);
+ break;
+
case CALL_INSN_OPCODE:
int3_emulate_call(regs, (long)ip + tp->rel32);
break;
@@ -1240,6 +1244,7 @@ static void text_poke_loc_init(struct te
switch (tp->opcode) {
case INT3_INSN_OPCODE:
+ case RET_INSN_OPCODE:
break;
case CALL_INSN_OPCODE:
next prev parent reply other threads:[~2020-06-24 15:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 15:30 [PATCH v5 00/17] Add static_call() Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 01/17] notifier: Fix broken error handling pattern Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 02/17] module: Fix up module_notifier return values Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 03/17] module: Properly propagate MODULE_STATE_COMING failure Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 04/17] jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 05/17] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 06/17] static_call: Add basic static call infrastructure Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 07/17] static_call: Add inline " Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 08/17] static_call: Avoid kprobes on inline static_call()s Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 09/17] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 10/17] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 11/17] static_call: Simple self-test Peter Zijlstra
2020-06-24 15:30 ` Peter Zijlstra [this message]
2020-06-24 15:30 ` [PATCH v5 13/17] static_call: Add static_call_cond() Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 14/17] static_call: Handle tail-calls Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 15/17] static_call: Allow early init Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 16/17] tracepoint: Optimize using static_call() Peter Zijlstra
2020-07-09 8:58 ` [PATCH v5.1 " Peter Zijlstra
2020-06-24 15:30 ` [PATCH v5 17/17] x86/perf, static_call: Optimize x86_pmu methods Peter Zijlstra
2020-07-09 11:16 ` Peter Zijlstra
2020-07-09 9:02 ` [PATCH v5 00/17] Add static_call() Peter Zijlstra
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