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From: Raphael Gault <raphael.gault@arm.com>
To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: julien.thierry@arm.com, peterz@infradead.org,
	catalin.marinas@arm.com, will.deacon@arm.com,
	Raphael Gault <raphael.gault@arm.com>,
	jpoimboe@redhat.com
Subject: [RFC 05/16] objtool: arm64: Handle hypercalls as nops
Date: Thu, 16 May 2019 11:36:44 +0100	[thread overview]
Message-ID: <20190516103655.5509-6-raphael.gault@arm.com> (raw)
In-Reply-To: <20190516103655.5509-1-raphael.gault@arm.com>

We consider that the hypervisor/secure-monitor is behaving
correctly. This enables us to handle hvc/smc/svc context switching
instructions as nop since we consider that the context is restored
correctly. This enables us to get rid of the "unsupported instruction
in callable function" warning which is not really useful.

Note that those instruction/warnings are caused by hypervisor-related
calls.

Signed-off-by: Raphael Gault <raphael.gault@arm.com>
---
 tools/objtool/arch/arm64/decode.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c
index 721152342dd3..6c77ad1a08ec 100644
--- a/tools/objtool/arch/arm64/decode.c
+++ b/tools/objtool/arch/arm64/decode.c
@@ -577,8 +577,11 @@ int arm_decode_except_gen(u32 instr, unsigned char *type,
 	case INSN_SVC:
 	case INSN_HVC:
 	case INSN_SMC:
-		*immediate = imm16;
-		*type = INSN_CONTEXT_SWITCH;
+		/*
+		 * We consider that the context will be restored correctly
+		 * with an unchanged sp and the same general registers
+		 */
+		*type = INSN_NOP;
 		return 0;
 	case INSN_BRK:
 		if (imm16 == 0x800)
-- 
2.17.1


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  parent reply	other threads:[~2019-05-16 10:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-16 10:36 [RFC V2 00/16] objtool: Add support for Arm64 Raphael Gault
2019-05-16 10:36 ` [RFC 01/16] objtool: Add abstraction for computation of symbols offsets Raphael Gault
2019-05-16 10:36 ` [RFC 02/16] objtool: orc: Refactor ORC API for other architectures to implement Raphael Gault
2019-05-16 10:36 ` [RFC 03/16] objtool: Move registers and control flow to arch-dependent code Raphael Gault
2019-05-16 10:36 ` [RFC 04/16] objtool: arm64: Add required implementation for supporting the aarch64 architecture in objtool Raphael Gault
2019-05-16 10:36 ` Raphael Gault [this message]
2019-05-16 10:36 ` [RFC 06/16] arm64: alternative: Mark .altinstr_replacement as containing executable instructions Raphael Gault
2019-05-16 10:36 ` [RFC 07/16] objtool: special: Adapt special section handling Raphael Gault
2019-05-16 10:36 ` [RFC 08/16] objtool: arm64: Adapt the stack frame checks for arm architecture Raphael Gault
2019-05-16 10:36 ` [RFC 09/16] arm64: assembler: Add macro to annotate asm function having non standard stack-frame Raphael Gault
2019-05-16 10:36 ` [RFC 10/16] arm64: sleep: Prevent stack frame warnings from objtool Raphael Gault
2019-05-16 10:36 ` [RFC 11/16] objtool: arm64: Enable stack validation for arm64 Raphael Gault
2019-05-16 10:36 ` [RFC 12/16] arm64: kvm: Annotate non-standard stack frame functions Raphael Gault
2019-05-16 10:36 ` [RFC 13/16] arm64: kernel: Add exception on kuser32 to prevent stack analysis Raphael Gault
2019-05-16 10:36 ` [RFC 14/16] arm64: crypto: Add exceptions for crypto object " Raphael Gault
2019-05-16 10:36 ` [RFC 15/16] objtool: Introduce INSN_UNKNOWN type Raphael Gault
2019-05-16 10:36 ` [RFC 16/16] arm64: kernel: Annotate non-standard stack frame functions Raphael Gault
2019-05-16 14:29 ` [RFC V2 00/16] objtool: Add support for Arm64 Josh Poimboeuf
2019-05-21 12:50   ` Raphael Gault
2019-05-22 23:11     ` Josh Poimboeuf
2019-05-23  7:31       ` Raphael Gault
2019-05-23  7:59       ` Raphael Gault
2019-05-28 22:24     ` Josh Poimboeuf
2019-06-13 15:55       ` Raphael Gault
2019-06-13 16:09         ` Josh Poimboeuf

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