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From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Miroslav Benes <mbenes@suse.cz>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Julien Thierry <jthierry@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	peterz@infradead.org
Subject: [PATCH 2/5] objtool: More consistent use of arch_callee_saved_reg()
Date: Wed, 03 Feb 2021 13:02:24 +0100	[thread overview]
Message-ID: <20210203120401.134132370@infradead.org> (raw)
In-Reply-To: 20210203120222.451068583@infradead.org

Since save_regs() will only ever set a reg when it is
arch_callee_saved_reg() all the other regs will always be unused and
are effectively scratch space.

No point in comparing them.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 tools/objtool/check.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1725,6 +1725,9 @@ static bool has_modified_stack_frame(str
 		return false;
 
 	for (i = 0; i < CFI_NUM_REGS; i++) {
+		if (!arch_callee_saved_reg(i))
+			continue;
+
 		if (cfi->regs[i].base != initial_func_cfi.regs[i].base ||
 		    cfi->regs[i].offset != initial_func_cfi.regs[i].offset)
 			return true;
@@ -2248,6 +2251,9 @@ static bool insn_cfi_match(struct instru
 
 	} else if (memcmp(&cfi1->regs, &cfi2->regs, sizeof(cfi1->regs))) {
 		for (i = 0; i < CFI_NUM_REGS; i++) {
+			if (!arch_callee_saved_reg(i))
+				continue;
+
 			if (!memcmp(&cfi1->regs[i], &cfi2->regs[i],
 				    sizeof(struct cfi_reg)))
 				continue;



  parent reply	other threads:[~2021-02-03 12:05 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-03 12:02 [PATCH 0/5] objtool: The stack swizzle again Peter Zijlstra
2021-02-03 12:02 ` [PATCH 1/5] objtool: Change REG_SP_INDIRECT Peter Zijlstra
2021-02-03 14:42   ` Josh Poimboeuf
2021-02-03 14:49     ` Peter Zijlstra
2021-02-03 14:55       ` Josh Poimboeuf
2021-02-03 12:02 ` Peter Zijlstra [this message]
2021-02-03 12:02 ` [PATCH 3/5] objtool: Prepare for scratch regs Peter Zijlstra
2021-02-03 12:02 ` [PATCH 4/5] objtool,x86: Additionally decode: mov %rsp, (%reg) Peter Zijlstra
2021-02-03 12:02 ` [PATCH 5/5] objtool: Support stack-swizzle Peter Zijlstra

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