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From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Juergen Gross <jgross@suse.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: objtool/core] x86/xen: Make save_fl() noinstr
Date: Wed, 15 Sep 2021 15:49:20 -0000	[thread overview]
Message-ID: <163172096099.25758.6758998678846375280.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210624095148.749712274@infradead.org>

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     1126696d60d04b844be88db50099f8fdb43d8166
Gitweb:        https://git.kernel.org/tip/1126696d60d04b844be88db50099f8fdb43d8166
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Thu, 24 Jun 2021 11:41:17 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 15 Sep 2021 15:51:49 +02:00

x86/xen: Make save_fl() noinstr

vmlinux.o: warning: objtool: pv_ops[30]: native_save_fl
vmlinux.o: warning: objtool: pv_ops[30]: __raw_callee_save_xen_save_fl
vmlinux.o: warning: objtool: pv_ops[30]: xen_save_fl_direct
vmlinux.o: warning: objtool: lockdep_hardirqs_off()+0x73: call to pv_ops[30]() leaves .noinstr.text section

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210624095148.749712274@infradead.org
---
 arch/x86/include/asm/paravirt.h |  7 +++++--
 arch/x86/kernel/irqflags.S      |  2 ++-
 arch/x86/xen/irq.c              |  4 ++--
 arch/x86/xen/xen-asm.S          | 32 ++++++++++++++++----------------
 4 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 34da790..cebec95 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -653,10 +653,10 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
  * functions.
  */
 #define PV_THUNK_NAME(func) "__raw_callee_save_" #func
-#define PV_CALLEE_SAVE_REGS_THUNK(func)					\
+#define __PV_CALLEE_SAVE_REGS_THUNK(func, section)			\
 	extern typeof(func) __raw_callee_save_##func;			\
 									\
-	asm(".pushsection .text;"					\
+	asm(".pushsection " section ", \"ax\";"				\
 	    ".globl " PV_THUNK_NAME(func) ";"				\
 	    ".type " PV_THUNK_NAME(func) ", @function;"			\
 	    PV_THUNK_NAME(func) ":"					\
@@ -669,6 +669,9 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
 	    ".size " PV_THUNK_NAME(func) ", .-" PV_THUNK_NAME(func) ";"	\
 	    ".popsection")
 
+#define PV_CALLEE_SAVE_REGS_THUNK(func)			\
+	__PV_CALLEE_SAVE_REGS_THUNK(func, ".text")
+
 /* Get a reference to a callee-save function */
 #define PV_CALLEE_SAVE(func)						\
 	((struct paravirt_callee_save) { __raw_callee_save_##func })
diff --git a/arch/x86/kernel/irqflags.S b/arch/x86/kernel/irqflags.S
index 8ef3506..760e1f2 100644
--- a/arch/x86/kernel/irqflags.S
+++ b/arch/x86/kernel/irqflags.S
@@ -7,9 +7,11 @@
 /*
  * unsigned long native_save_fl(void)
  */
+.pushsection .noinstr.text, "ax"
 SYM_FUNC_START(native_save_fl)
 	pushf
 	pop %_ASM_AX
 	ret
 SYM_FUNC_END(native_save_fl)
+.popsection
 EXPORT_SYMBOL(native_save_fl)
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index dfa091d..9c71f43 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -24,7 +24,7 @@ void xen_force_evtchn_callback(void)
 	(void)HYPERVISOR_xen_version(0, NULL);
 }
 
-asmlinkage __visible unsigned long xen_save_fl(void)
+asmlinkage __visible noinstr unsigned long xen_save_fl(void)
 {
 	struct vcpu_info *vcpu;
 	unsigned long flags;
@@ -40,7 +40,7 @@ asmlinkage __visible unsigned long xen_save_fl(void)
 	*/
 	return (-flags) & X86_EFLAGS_IF;
 }
-PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
+__PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl, ".noinstr.text");
 
 asmlinkage __visible void xen_irq_disable(void)
 {
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index aef4a1e..0883e39 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -58,22 +58,6 @@ SYM_FUNC_START(xen_irq_disable_direct)
 SYM_FUNC_END(xen_irq_disable_direct)
 
 /*
- * (xen_)save_fl is used to get the current interrupt enable status.
- * Callers expect the status to be in X86_EFLAGS_IF, and other bits
- * may be set in the return value.  We take advantage of this by
- * making sure that X86_EFLAGS_IF has the right value (and other bits
- * in that byte are 0), but other bits in the return value are
- * undefined.  We need to toggle the state of the bit, because Xen and
- * x86 use opposite senses (mask vs enable).
- */
-SYM_FUNC_START(xen_save_fl_direct)
-	testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
-	setz %ah
-	addb %ah, %ah
-	ret
-SYM_FUNC_END(xen_save_fl_direct)
-
-/*
  * Force an event check by making a hypercall, but preserve regs
  * before making the call.
  */
@@ -103,6 +87,22 @@ SYM_FUNC_START(check_events)
 SYM_FUNC_END(check_events)
 
 .pushsection .noinstr.text, "ax"
+/*
+ * (xen_)save_fl is used to get the current interrupt enable status.
+ * Callers expect the status to be in X86_EFLAGS_IF, and other bits
+ * may be set in the return value.  We take advantage of this by
+ * making sure that X86_EFLAGS_IF has the right value (and other bits
+ * in that byte are 0), but other bits in the return value are
+ * undefined.  We need to toggle the state of the bit, because Xen and
+ * x86 use opposite senses (mask vs enable).
+ */
+SYM_FUNC_START(xen_save_fl_direct)
+	testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
+	setz %ah
+	addb %ah, %ah
+	ret
+SYM_FUNC_END(xen_save_fl_direct)
+
 SYM_FUNC_START(xen_read_cr2)
 	FRAME_BEGIN
 	_ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX

  parent reply	other threads:[~2021-09-15 15:49 UTC|newest]

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-24  9:40 [PATCH v2 00/24] objtool/x86: noinstr vs PARAVIRT Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 01/24] x86/xen: Mark cpu_bringup_and_idle() as dead_end_function Peter Zijlstra
2021-06-24 10:49   ` Juergen Gross
2021-06-30 11:47   ` Miroslav Benes
2021-08-20 19:22   ` Josh Poimboeuf
2021-08-20 19:31     ` Josh Poimboeuf
2021-08-23  8:40       ` Juergen Gross
2021-08-30  5:55         ` Juergen Gross
2021-08-30  7:48           ` Peter Zijlstra
2021-08-30  7:56             ` Juergen Gross
2021-09-15 15:49       ` [tip: objtool/core] x86/xen: Move hypercall_page to top of the file tip-bot2 for Josh Poimboeuf
2021-09-15 15:49   ` [tip: objtool/core] x86/xen: Mark cpu_bringup_and_idle() as dead_end_function tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 02/24] objtool: Introduce CFI hash Peter Zijlstra
2021-06-30 12:45   ` Miroslav Benes
2021-07-01  8:35     ` Peter Zijlstra
2021-07-01  8:53       ` Miroslav Benes
2021-08-20 22:27   ` Josh Poimboeuf
2021-08-25 10:13     ` Peter Zijlstra
2021-08-25 12:49       ` Peter Zijlstra
2021-08-25 10:15     ` Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 03/24] objtool: Handle __sanitize_cov*() tail calls Peter Zijlstra
2021-06-25 11:05   ` Marco Elver
2021-06-28  9:07     ` Peter Zijlstra
2021-06-25 13:38   ` Steven Rostedt
2021-06-26  8:18     ` Peter Zijlstra
2021-06-29  1:07       ` Steven Rostedt
2021-08-20 23:17   ` Josh Poimboeuf
2021-08-25 10:19     ` Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 04/24] x86/kvm: Always inline sev_*guest() Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 05/24] x86/kvm: Always inline vmload() / vmsave() Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 06/24] x86: Always inline context_tracking_guest_enter() Peter Zijlstra
2021-08-20 23:22   ` Josh Poimboeuf
2021-08-20 23:34     ` Josh Poimboeuf
2021-08-25 12:16       ` Peter Zijlstra
     [not found]         ` <YSZxtBHNJzoUbqdE@ravnborg.org>
2021-08-26  4:10           ` Josh Poimboeuf
2021-08-25 13:38       ` Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 07/24] x86/kvm: Always inline to_svm() Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 08/24] x86/kvm: Always inline evmcs_write64() Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 09/24] x86: Always inline ip_within_syscall_gap() Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 10/24] x86/sev: Fix noinstr for vc_ghcb_invalidate() Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 11/24] locking/lockdep: Avoid RCU-induced noinstr fail Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 12/24] x86/paravirt: Mark arch_local_irq_*() __always_inline Peter Zijlstra
2021-06-24 10:51   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 13/24] x86/paravirt: Use PVOP_* for paravirt calls Peter Zijlstra
2021-06-24 10:52   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 14/24] x86/xen: Make read_cr2() noinstr Peter Zijlstra
2021-06-24 10:55   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 15/24] x86/xen: Make write_cr2() noinstr Peter Zijlstra
2021-06-24 10:56   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 16/24] x86/xen: Make get_debugreg() noinstr Peter Zijlstra
2021-06-24 10:57   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 17/24] x86/xen: Make set_debugreg() noinstr Peter Zijlstra
2021-06-24 10:59   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 18/24] x86/xen: Make save_fl() noinstr Peter Zijlstra
2021-06-24 11:07   ` Juergen Gross
2021-09-15 15:49   ` tip-bot2 for Peter Zijlstra [this message]
2021-09-17 12:58   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 19/24] x86/xen: Make hypercall_page noinstr Peter Zijlstra
2021-06-24 11:08   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 20/24] x86/xen: Make irq_enable() noinstr Peter Zijlstra
2021-06-24 11:09   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 21/24] x86/xen: Make irq_disable() noinstr Peter Zijlstra
2021-06-24 11:10   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 22/24] x86/xen: Mark xen_force_evtchn_callback() noinstr Peter Zijlstra
2021-06-24 11:11   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 23/24] x86/xen: Rework the xen_{cpu,irq,mmu}_ops[] arrays Peter Zijlstra
2021-06-24 12:12   ` Juergen Gross
2021-09-15 15:49   ` [tip: objtool/core] x86/xen: Rework the xen_{cpu,irq,mmu}_opsarrays tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24  9:41 ` [PATCH v2 24/24] objtool: Support pv_opsindirect calls for noinstr Peter Zijlstra
2021-09-15 15:49   ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2021-09-17 12:58   ` tip-bot2 for Peter Zijlstra
2021-06-24 13:05 ` [PATCH v2 00/24] objtool/x86: noinstr vs PARAVIRT Steven Rostedt

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