Message ID | 20230317160546.1497477-1-gpiccoli@igalia.com |
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Piccoli" <gpiccoli@igalia.com> To: linux-hyperv@vger.kernel.org, x86@kernel.org Cc: linux-kernel@vger.kernel.org, decui@microsoft.com, haiyangz@microsoft.com, kys@microsoft.com, wei.liu@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, thomas.lendacky@amd.com, peterz@infradead.org, kernel-dev@igalia.com, kernel@gpiccoli.net, "Guilherme G. Piccoli" <gpiccoli@igalia.com>, Arnd Bergmann <arnd@arndb.de>, Josh Poimboeuf <jpoimboe@kernel.org>, Michael Kelley <mikelley@microsoft.com> Subject: [PATCH v3] x86/hyperv: Mark hv_ghcb_terminate() as noreturn Date: Fri, 17 Mar 2023 13:05:46 -0300 Message-Id: <20230317160546.1497477-1-gpiccoli@igalia.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230310154452.1169204-1-gpiccoli@igalia.com> References: <20230310154452.1169204-1-gpiccoli@igalia.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: <linux-kernel.vger.kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759997059728087181?= X-GMAIL-MSGID: =?utf-8?q?1760632952027997635?= |
Series |
[v3] x86/hyperv: Mark hv_ghcb_terminate() as noreturn
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Commit Message
Guilherme G. Piccoli
March 17, 2023, 4:05 p.m. UTC
Annotate the function prototype and definition as noreturn to prevent
objtool warnings like:
vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction
Also, as per Josh's suggestion, add it to the global_noreturns list.
As a comparison, an objdump output without the annotation:
[...]
1b63: mov $0x1,%esi
1b68: xor %edi,%edi
1b6a: callq ffffffff8102f680 <hv_ghcb_terminate>
1b6f: jmpq ffffffff82f217ec <hyperv_init+0x9c> # unreachable
1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip)
[...]
Now, after adding the __noreturn to the function prototype:
[...]
17df: callq ffffffff8102f6d0 <hv_ghcb_negotiate_protocol>
17e4: test %al,%al
17e6: je ffffffff82f21bb9 <hyperv_init+0x469>
[...] <many insns>
1bb9: mov $0x1,%esi
1bbe: xor %edi,%edi
1bc0: callq ffffffff8102f680 <hv_ghcb_terminate>
1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function
Reported-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/9698eff1-9680-4f0a-94de-590eaa923e94@app.fastmail.com/
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
---
V3:
- As per Michael / Josh advice (thanks!), added __noreturn to the
function definition as well.
V2:
- Per Josh's suggestion (thanks!), added the function name to the
objtool global table.
Thanks in advance for reviews/comments!
Cheers,
Guilherme
arch/x86/hyperv/ivm.c | 2 +-
arch/x86/include/asm/mshyperv.h | 2 +-
tools/objtool/check.c | 1 +
3 files changed, 3 insertions(+), 2 deletions(-)
Comments
On Fri, Mar 17, 2023 at 01:05:46PM -0300, Guilherme G. Piccoli wrote: > Annotate the function prototype and definition as noreturn to prevent > objtool warnings like: > > vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction > > Also, as per Josh's suggestion, add it to the global_noreturns list. > As a comparison, an objdump output without the annotation: > > [...] > 1b63: mov $0x1,%esi > 1b68: xor %edi,%edi > 1b6a: callq ffffffff8102f680 <hv_ghcb_terminate> > 1b6f: jmpq ffffffff82f217ec <hyperv_init+0x9c> # unreachable > 1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip) > [...] > > Now, after adding the __noreturn to the function prototype: > > [...] > 17df: callq ffffffff8102f6d0 <hv_ghcb_negotiate_protocol> > 17e4: test %al,%al > 17e6: je ffffffff82f21bb9 <hyperv_init+0x469> > [...] <many insns> > 1bb9: mov $0x1,%esi > 1bbe: xor %edi,%edi > 1bc0: callq ffffffff8102f680 <hv_ghcb_terminate> > 1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function > > Reported-by: Arnd Bergmann <arnd@arndb.de> > Link: https://lore.kernel.org/r/9698eff1-9680-4f0a-94de-590eaa923e94@app.fastmail.com/ > Cc: Josh Poimboeuf <jpoimboe@kernel.org> > Cc: Michael Kelley <mikelley@microsoft.com> > Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Looks good to me. I've got some other noreturn fixes pending, so I can add this patch to the pile unless somebody else wants to take it.
From: Guilherme G. Piccoli <gpiccoli@igalia.com> Sent: Friday, March 17, 2023 9:06 AM > > Annotate the function prototype and definition as noreturn to prevent > objtool warnings like: > > vmlinux.o: warning: objtool: hyperv_init+0x55c: unreachable instruction > > Also, as per Josh's suggestion, add it to the global_noreturns list. > As a comparison, an objdump output without the annotation: > > [...] > 1b63: mov $0x1,%esi > 1b68: xor %edi,%edi > 1b6a: callq ffffffff8102f680 <hv_ghcb_terminate> > 1b6f: jmpq ffffffff82f217ec <hyperv_init+0x9c> # unreachable > 1b74: cmpq $0xffffffffffffffff,-0x702a24(%rip) > [...] > > Now, after adding the __noreturn to the function prototype: > > [...] > 17df: callq ffffffff8102f6d0 <hv_ghcb_negotiate_protocol> > 17e4: test %al,%al > 17e6: je ffffffff82f21bb9 <hyperv_init+0x469> > [...] <many insns> > 1bb9: mov $0x1,%esi > 1bbe: xor %edi,%edi > 1bc0: callq ffffffff8102f680 <hv_ghcb_terminate> > 1bc5: nopw %cs:0x0(%rax,%rax,1) # end of function > > Reported-by: Arnd Bergmann <arnd@arndb.de> > Link: https://lore.kernel.org/all/9698eff1-9680-4f0a-94de-590eaa923e94@app.fastmail.com/ > Cc: Josh Poimboeuf <jpoimboe@kernel.org> > Cc: Michael Kelley <mikelley@microsoft.com> > Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> > --- > > > V3: > - As per Michael / Josh advice (thanks!), added __noreturn to the > function definition as well. > > V2: > - Per Josh's suggestion (thanks!), added the function name to the > objtool global table. > > Thanks in advance for reviews/comments! > Cheers, > > Guilherme > > > arch/x86/hyperv/ivm.c | 2 +- > arch/x86/include/asm/mshyperv.h | 2 +- > tools/objtool/check.c | 1 + > 3 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c > index 1dbcbd9da74d..4f79dc76042d 100644 > --- a/arch/x86/hyperv/ivm.c > +++ b/arch/x86/hyperv/ivm.c > @@ -127,7 +127,7 @@ static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 > exit_code, > return ES_OK; > } > > -void hv_ghcb_terminate(unsigned int set, unsigned int reason) > +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason) > { > u64 val = GHCB_MSR_TERM_REQ; > > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index 4c4c0ec3b62e..09c26e658bcc 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -212,7 +212,7 @@ int hv_set_mem_host_visibility(unsigned long addr, int > numpages, bool visible); > void hv_ghcb_msr_write(u64 msr, u64 value); > void hv_ghcb_msr_read(u64 msr, u64 *value); > bool hv_ghcb_negotiate_protocol(void); > -void hv_ghcb_terminate(unsigned int set, unsigned int reason); > +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason); > #else > static inline void hv_ghcb_msr_write(u64 msr, u64 value) {} > static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {} > diff --git a/tools/objtool/check.c b/tools/objtool/check.c > index f937be1afe65..4b5e03f61f1f 100644 > --- a/tools/objtool/check.c > +++ b/tools/objtool/check.c > @@ -209,6 +209,7 @@ static bool __dead_end_function(struct objtool_file *file, struct > symbol *func, > "do_task_dead", > "ex_handler_msr_mce", > "fortify_panic", > + "hv_ghcb_terminate", > "kthread_complete_and_exit", > "kthread_exit", > "kunit_try_catch_throw", > -- > 2.39.2 Reviewed-by: Michael Kelley <mikelley@microsoft.com>
On 17/03/2023 13:24, Josh Poimboeuf wrote: > [...] > > Looks good to me. I've got some other noreturn fixes pending, so I can > add this patch to the pile unless somebody else wants to take it. Thanks, that'd be great. And thanks Michael for your review =)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index 1dbcbd9da74d..4f79dc76042d 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -127,7 +127,7 @@ static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code, return ES_OK; } -void hv_ghcb_terminate(unsigned int set, unsigned int reason) +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason) { u64 val = GHCB_MSR_TERM_REQ; diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 4c4c0ec3b62e..09c26e658bcc 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -212,7 +212,7 @@ int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible); void hv_ghcb_msr_write(u64 msr, u64 value); void hv_ghcb_msr_read(u64 msr, u64 *value); bool hv_ghcb_negotiate_protocol(void); -void hv_ghcb_terminate(unsigned int set, unsigned int reason); +void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason); #else static inline void hv_ghcb_msr_write(u64 msr, u64 value) {} static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {} diff --git a/tools/objtool/check.c b/tools/objtool/check.c index f937be1afe65..4b5e03f61f1f 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -209,6 +209,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "do_task_dead", "ex_handler_msr_mce", "fortify_panic", + "hv_ghcb_terminate", "kthread_complete_and_exit", "kthread_exit", "kunit_try_catch_throw",