[PATCH -tip 1/5] x86/irq/32: Use named operands in inline asm

[PATCH -tip 1/5] x86/irq/32: Use named operands in inline asm

[Uros Bizjak]

Also use inout "+" constraint modifier where appropriate.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/kernel/irq_32.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index dc1049c01f9b..c4719c40252f 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -54,12 +54,11 @@ static inline void print_stack_overflow(void) { }
 
 static void call_on_stack(void *func, void *stack)
 {
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=b" (stack)
-		     : "0" (stack),
-		       [thunk_target] "D"(func)
+		     "movl %[sp], %%esp"
+		     : [sp] "+b" (stack)
+		     : [thunk_target] "D" (func)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -71,7 +70,7 @@ static inline void *current_stack(void)
 static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
-	u32 *isp, *prev_esp, arg1;
+	u32 *isp, *prev_esp;
 
 	curstk = (struct irq_stack *) current_stack();
 	irqstk = __this_cpu_read(pcpu_hot.hardirq_stack_ptr);
@@ -94,12 +93,11 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	if (unlikely(overflow))
 		call_on_stack(print_stack_overflow, isp);
 
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=a" (arg1), "=b" (isp)
-		     :  "0" (desc),   "1" (isp),
-			[thunk_target] "D" (desc->handle_irq)
+		     "movl %[sp], %%esp"
+		     : "+a" (desc), [sp] "+b" (isp)
+		     : [thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "ecx");
 	return 1;
 }
-- 
2.42.0

[PATCH -tip 2/5] x86/irq/32: Add missing clobber to inline asm

[Uros Bizjak]

i386 ABI declares %edx as a call-clobbered register.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/kernel/irq_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index c4719c40252f..eab458009f97 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
-		     : "memory", "cc", "ecx");
+		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }
 
-- 
2.42.0

[PATCH -tip 3/5] x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

[Uros Bizjak]

This constraint should be used for any inline asm which has a CALL
instruction, otherwise the compiler may schedule the asm before the
frame pointer gets set up by the containing function, causing objtool
to print a "call without frame pointer save/setup" warning.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/kernel/irq_32.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index eab458009f97..f351fa1ee6a7 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -59,6 +59,7 @@ static void call_on_stack(void *func, void *stack)
 		     "movl %[sp], %%esp"
 		     : [sp] "+b" (stack)
 		     : [thunk_target] "D" (func)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -98,6 +99,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }
-- 
2.42.0

[PATCH -tip 4/5] x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

[Uros Bizjak]

Make code more readable by using current_stack_pointer global variable.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/kernel/irq_32.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index f351fa1ee6a7..2428d661faaf 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -31,10 +31,7 @@ int sysctl_panic_on_stackoverflow __read_mostly;
 /* Debugging check for stack overflow: is there less than 1KB free? */
 static int check_stack_overflow(void)
 {
-	long sp;
-
-	__asm__ __volatile__("andl %%esp,%0" :
-			     "=r" (sp) : "0" (THREAD_SIZE - 1));
+	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
 	return sp < (sizeof(struct thread_info) + STACK_WARN);
 }
-- 
2.42.0

[PATCH -tip 5/5] x86/irq/32: Change some static functions to bool

[Uros Bizjak]

The return values of some functions are of boolean type. Change the
type of these function to bool and adjust their return values.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/kernel/irq_32.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 2428d661faaf..566a93ddf418 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -29,7 +29,7 @@
 int sysctl_panic_on_stackoverflow __read_mostly;
 
 /* Debugging check for stack overflow: is there less than 1KB free? */
-static int check_stack_overflow(void)
+static bool check_stack_overflow(void)
 {
 	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
@@ -45,7 +45,7 @@ static void print_stack_overflow(void)
 }
 
 #else
-static inline int check_stack_overflow(void) { return 0; }
+static inline bool check_stack_overflow(void) { return false; }
 static inline void print_stack_overflow(void) { }
 #endif
 
@@ -65,7 +65,7 @@ static inline void *current_stack(void)
 	return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1));
 }
 
-static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
+static inline bool execute_on_irq_stack(bool overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
 	u32 *isp, *prev_esp;
@@ -80,7 +80,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (unlikely(curstk == irqstk))
-		return 0;
+		return false;
 
 	isp = (u32 *) ((char *)irqstk + sizeof(*irqstk));
 
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     : [thunk_target] "D" (desc->handle_irq)
 		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
-	return 1;
+	return true;
 }
 
 /*
@@ -147,7 +147,7 @@ void do_softirq_own_stack(void)
 
 void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
-	int overflow = check_stack_overflow();
+	bool overflow = check_stack_overflow();
 
 	if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) {
 		if (unlikely(overflow))
-- 
2.42.0

[tip: x86/asm] x86/irq/32: Change some static functions to bool

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     45f6469225e8da92ff1e5ec1027431053ba397c0
Gitweb:        https://git.kernel.org/tip/45f6469225e8da92ff1e5ec1027431053ba397c0
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:25 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 10:53:52 +01:00

x86/irq/32: Change some static functions to bool

The return values of these functions is 0/1, but they use an int
type instead of bool:

  check_stack_overflow()
  execute_on_irq_stack()

Change the type of these function to bool and adjust their return
values and affected helper variables.

[ mingo: Rewrote the changelog ]

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-5-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 2428d66..566a93d 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -29,7 +29,7 @@
 int sysctl_panic_on_stackoverflow __read_mostly;
 
 /* Debugging check for stack overflow: is there less than 1KB free? */
-static int check_stack_overflow(void)
+static bool check_stack_overflow(void)
 {
 	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
@@ -45,7 +45,7 @@ static void print_stack_overflow(void)
 }
 
 #else
-static inline int check_stack_overflow(void) { return 0; }
+static inline bool check_stack_overflow(void) { return false; }
 static inline void print_stack_overflow(void) { }
 #endif
 
@@ -65,7 +65,7 @@ static inline void *current_stack(void)
 	return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1));
 }
 
-static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
+static inline bool execute_on_irq_stack(bool overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
 	u32 *isp, *prev_esp;
@@ -80,7 +80,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (unlikely(curstk == irqstk))
-		return 0;
+		return false;
 
 	isp = (u32 *) ((char *)irqstk + sizeof(*irqstk));
 
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     : [thunk_target] "D" (desc->handle_irq)
 		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
-	return 1;
+	return true;
 }
 
 /*
@@ -147,7 +147,7 @@ void do_softirq_own_stack(void)
 
 void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
-	int overflow = check_stack_overflow();
+	bool overflow = check_stack_overflow();
 
 	if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) {
 		if (unlikely(overflow))

[tip: x86/asm] x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     70e8a96f5408e409dc71b08a366d6d705e9d9fb8
Gitweb:        https://git.kernel.org/tip/70e8a96f5408e409dc71b08a366d6d705e9d9fb8
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:24 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 10:53:51 +01:00

x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

Make code more readable by using the 'current_stack_pointer' global variable.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-4-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index f351fa1..2428d66 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -31,10 +31,7 @@ int sysctl_panic_on_stackoverflow __read_mostly;
 /* Debugging check for stack overflow: is there less than 1KB free? */
 static int check_stack_overflow(void)
 {
-	long sp;
-
-	__asm__ __volatile__("andl %%esp,%0" :
-			     "=r" (sp) : "0" (THREAD_SIZE - 1));
+	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
 	return sp < (sizeof(struct thread_info) + STACK_WARN);
 }

[tip: x86/asm] x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     94770fe8648b80ee7ec4484e43b2381a25b62746
Gitweb:        https://git.kernel.org/tip/94770fe8648b80ee7ec4484e43b2381a25b62746
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:23 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 10:53:51 +01:00

x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

This constraint should be used for any inline asm which has a CALL
instruction, otherwise the compiler may schedule the asm before the
frame pointer gets set up by the containing function, causing objtool
to print a "call without frame pointer save/setup" warning.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-3-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index eab4580..f351fa1 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -59,6 +59,7 @@ static void call_on_stack(void *func, void *stack)
 		     "movl %[sp], %%esp"
 		     : [sp] "+b" (stack)
 		     : [thunk_target] "D" (func)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -98,6 +99,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }

[tip: x86/asm] x86/irq/32: Add missing clobber to inline asm

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     553d9797b9a161ae98072250bbe7ba4cec03cb87
Gitweb:        https://git.kernel.org/tip/553d9797b9a161ae98072250bbe7ba4cec03cb87
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:22 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 10:53:51 +01:00

x86/irq/32: Add missing clobber to inline asm

i386 ABI declares %edx as a call-clobbered register.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-2-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index c4719c4..eab4580 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
-		     : "memory", "cc", "ecx");
+		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }
 

[tip: x86/asm] x86/irq/32: Use named operands in inline asm

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     3fc50ac7607a18a60207901ad1604dae9b52701b
Gitweb:        https://git.kernel.org/tip/3fc50ac7607a18a60207901ad1604dae9b52701b
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:21 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 10:53:51 +01:00

x86/irq/32: Use named operands in inline asm

Also use inout "+" constraint modifier where appropriate.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-1-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index dc1049c..c4719c4 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -54,12 +54,11 @@ static inline void print_stack_overflow(void) { }
 
 static void call_on_stack(void *func, void *stack)
 {
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=b" (stack)
-		     : "0" (stack),
-		       [thunk_target] "D"(func)
+		     "movl %[sp], %%esp"
+		     : [sp] "+b" (stack)
+		     : [thunk_target] "D" (func)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -71,7 +70,7 @@ static inline void *current_stack(void)
 static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
-	u32 *isp, *prev_esp, arg1;
+	u32 *isp, *prev_esp;
 
 	curstk = (struct irq_stack *) current_stack();
 	irqstk = __this_cpu_read(pcpu_hot.hardirq_stack_ptr);
@@ -94,12 +93,11 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	if (unlikely(overflow))
 		call_on_stack(print_stack_overflow, isp);
 
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=a" (arg1), "=b" (isp)
-		     :  "0" (desc),   "1" (isp),
-			[thunk_target] "D" (desc->handle_irq)
+		     "movl %[sp], %%esp"
+		     : "+a" (desc), [sp] "+b" (isp)
+		     : [thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "ecx");
 	return 1;
 }

[tip: x86/asm] x86/irq/32: Change some static functions to bool

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     7b52de3a2811bf16f52b895478920113e1b39878
Gitweb:        https://git.kernel.org/tip/7b52de3a2811bf16f52b895478920113e1b39878
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:25 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 11:21:40 +01:00

x86/irq/32: Change some static functions to bool

The return values of these functions is 0/1, but they use an int
type instead of bool:

  check_stack_overflow()
  execute_on_irq_stack()

Change the type of these function to bool and adjust their return
values and affected helper variables.

[ mingo: Rewrote the changelog ]

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-5-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 2428d66..566a93d 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -29,7 +29,7 @@
 int sysctl_panic_on_stackoverflow __read_mostly;
 
 /* Debugging check for stack overflow: is there less than 1KB free? */
-static int check_stack_overflow(void)
+static bool check_stack_overflow(void)
 {
 	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
@@ -45,7 +45,7 @@ static void print_stack_overflow(void)
 }
 
 #else
-static inline int check_stack_overflow(void) { return 0; }
+static inline bool check_stack_overflow(void) { return false; }
 static inline void print_stack_overflow(void) { }
 #endif
 
@@ -65,7 +65,7 @@ static inline void *current_stack(void)
 	return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1));
 }
 
-static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
+static inline bool execute_on_irq_stack(bool overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
 	u32 *isp, *prev_esp;
@@ -80,7 +80,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (unlikely(curstk == irqstk))
-		return 0;
+		return false;
 
 	isp = (u32 *) ((char *)irqstk + sizeof(*irqstk));
 
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     : [thunk_target] "D" (desc->handle_irq)
 		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
-	return 1;
+	return true;
 }
 
 /*
@@ -147,7 +147,7 @@ void do_softirq_own_stack(void)
 
 void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
-	int overflow = check_stack_overflow();
+	bool overflow = check_stack_overflow();
 
 	if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) {
 		if (unlikely(overflow))

[tip: x86/asm] x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     9266be1052e0586ea932011ad671beefbaff1a64
Gitweb:        https://git.kernel.org/tip/9266be1052e0586ea932011ad671beefbaff1a64
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:24 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 11:21:40 +01:00

x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

Make code more readable by using the 'current_stack_pointer' global variable.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-4-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index f351fa1..2428d66 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -31,10 +31,7 @@ int sysctl_panic_on_stackoverflow __read_mostly;
 /* Debugging check for stack overflow: is there less than 1KB free? */
 static int check_stack_overflow(void)
 {
-	long sp;
-
-	__asm__ __volatile__("andl %%esp,%0" :
-			     "=r" (sp) : "0" (THREAD_SIZE - 1));
+	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
 	return sp < (sizeof(struct thread_info) + STACK_WARN);
 }

[tip: x86/asm] x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     4d93ca6d7e92584c559d8687ac9eef15251bb97b
Gitweb:        https://git.kernel.org/tip/4d93ca6d7e92584c559d8687ac9eef15251bb97b
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:23 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 11:21:40 +01:00

x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

This constraint should be used for any inline asm which has a CALL
instruction, otherwise the compiler may schedule the asm before the
frame pointer gets set up by the containing function, causing objtool
to print a "call without frame pointer save/setup" warning.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-3-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index eab4580..f351fa1 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -59,6 +59,7 @@ static void call_on_stack(void *func, void *stack)
 		     "movl %[sp], %%esp"
 		     : [sp] "+b" (stack)
 		     : [thunk_target] "D" (func)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -98,6 +99,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }

[tip: x86/asm] x86/irq/32: Add missing clobber to inline asm

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     40d9cd9bb08cbe36900efd1600e2228698d52b4a
Gitweb:        https://git.kernel.org/tip/40d9cd9bb08cbe36900efd1600e2228698d52b4a
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:22 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 11:21:40 +01:00

x86/irq/32: Add missing clobber to inline asm

i386 ABI declares %edx as a call-clobbered register.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-2-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index c4719c4..eab4580 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
-		     : "memory", "cc", "ecx");
+		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }
 

[tip: x86/asm] x86/irq/32: Use named operands in inline asm

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     df682f7b763e8d983ef70c4908f8980a2ffc81cd
Gitweb:        https://git.kernel.org/tip/df682f7b763e8d983ef70c4908f8980a2ffc81cd
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:21 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 11:21:40 +01:00

x86/irq/32: Use named operands in inline asm

Also use inout "+" constraint modifier where appropriate.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-1-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index dc1049c..c4719c4 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -54,12 +54,11 @@ static inline void print_stack_overflow(void) { }
 
 static void call_on_stack(void *func, void *stack)
 {
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=b" (stack)
-		     : "0" (stack),
-		       [thunk_target] "D"(func)
+		     "movl %[sp], %%esp"
+		     : [sp] "+b" (stack)
+		     : [thunk_target] "D" (func)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -71,7 +70,7 @@ static inline void *current_stack(void)
 static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
-	u32 *isp, *prev_esp, arg1;
+	u32 *isp, *prev_esp;
 
 	curstk = (struct irq_stack *) current_stack();
 	irqstk = __this_cpu_read(pcpu_hot.hardirq_stack_ptr);
@@ -94,12 +93,11 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	if (unlikely(overflow))
 		call_on_stack(print_stack_overflow, isp);
 
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=a" (arg1), "=b" (isp)
-		     :  "0" (desc),   "1" (isp),
-			[thunk_target] "D" (desc->handle_irq)
+		     "movl %[sp], %%esp"
+		     : "+a" (desc), [sp] "+b" (isp)
+		     : [thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "ecx");
 	return 1;
 }

[tip: x86/asm] x86/irq/32: Change some static functions to bool

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     9c5f9473dfa0b13af72b8f856e2c87d36acaed90
Gitweb:        https://git.kernel.org/tip/9c5f9473dfa0b13af72b8f856e2c87d36acaed90
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:25 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:12:40 +01:00

x86/irq/32: Change some static functions to bool

The return values of these functions is 0/1, but they use an int
type instead of bool:

  check_stack_overflow()
  execute_on_irq_stack()

Change the type of these function to bool and adjust their return
values and affected helper variables.

[ mingo: Rewrote the changelog ]

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-5-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 2428d66..566a93d 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -29,7 +29,7 @@
 int sysctl_panic_on_stackoverflow __read_mostly;
 
 /* Debugging check for stack overflow: is there less than 1KB free? */
-static int check_stack_overflow(void)
+static bool check_stack_overflow(void)
 {
 	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
@@ -45,7 +45,7 @@ static void print_stack_overflow(void)
 }
 
 #else
-static inline int check_stack_overflow(void) { return 0; }
+static inline bool check_stack_overflow(void) { return false; }
 static inline void print_stack_overflow(void) { }
 #endif
 
@@ -65,7 +65,7 @@ static inline void *current_stack(void)
 	return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1));
 }
 
-static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
+static inline bool execute_on_irq_stack(bool overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
 	u32 *isp, *prev_esp;
@@ -80,7 +80,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (unlikely(curstk == irqstk))
-		return 0;
+		return false;
 
 	isp = (u32 *) ((char *)irqstk + sizeof(*irqstk));
 
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     : [thunk_target] "D" (desc->handle_irq)
 		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
-	return 1;
+	return true;
 }
 
 /*
@@ -147,7 +147,7 @@ void do_softirq_own_stack(void)
 
 void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
-	int overflow = check_stack_overflow();
+	bool overflow = check_stack_overflow();
 
 	if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) {
 		if (unlikely(overflow))

[tip: x86/asm] x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     1aee47babaa440b92314199963c5ed3395dc4edb
Gitweb:        https://git.kernel.org/tip/1aee47babaa440b92314199963c5ed3395dc4edb
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:24 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:12:40 +01:00

x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

Make code more readable by using the 'current_stack_pointer' global variable.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-4-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index f351fa1..2428d66 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -31,10 +31,7 @@ int sysctl_panic_on_stackoverflow __read_mostly;
 /* Debugging check for stack overflow: is there less than 1KB free? */
 static int check_stack_overflow(void)
 {
-	long sp;
-
-	__asm__ __volatile__("andl %%esp,%0" :
-			     "=r" (sp) : "0" (THREAD_SIZE - 1));
+	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
 	return sp < (sizeof(struct thread_info) + STACK_WARN);
 }

[tip: x86/asm] x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     784af8f453fddec902639f42e2456f7fb5199450
Gitweb:        https://git.kernel.org/tip/784af8f453fddec902639f42e2456f7fb5199450
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:23 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:12:40 +01:00

x86/irq/32: Add ASM_CALL_CONSTRAINT to inline asm using CALL_NOSPEC

This constraint should be used for any inline asm which has a CALL
instruction, otherwise the compiler may schedule the asm before the
frame pointer gets set up by the containing function, causing objtool
to print a "call without frame pointer save/setup" warning.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-3-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index eab4580..f351fa1 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -59,6 +59,7 @@ static void call_on_stack(void *func, void *stack)
 		     "movl %[sp], %%esp"
 		     : [sp] "+b" (stack)
 		     : [thunk_target] "D" (func)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -98,6 +99,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
+		       COMMA(ASM_CALL_CONSTRAINT)
 		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }

[tip: x86/asm] x86/irq/32: Add missing clobber to inline asm

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     76f71137811a6dfa52b3e22a86a772e5753021d3
Gitweb:        https://git.kernel.org/tip/76f71137811a6dfa52b3e22a86a772e5753021d3
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:22 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:12:40 +01:00

x86/irq/32: Add missing clobber to inline asm

i386 ABI declares %edx as a call-clobbered register.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-2-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index c4719c4..eab4580 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -98,7 +98,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     "movl %[sp], %%esp"
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
-		     : "memory", "cc", "ecx");
+		     : "memory", "cc", "edx", "ecx");
 	return 1;
 }
 

[tip: x86/asm] x86/irq/32: Use named operands in inline asm

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     0ec914707c3ed052ed26eb88f9300109030a7fb2
Gitweb:        https://git.kernel.org/tip/0ec914707c3ed052ed26eb88f9300109030a7fb2
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:21 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:12:40 +01:00

x86/irq/32: Use named operands in inline asm

Also use inout "+" constraint modifier where appropriate.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-1-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index dc1049c..c4719c4 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -54,12 +54,11 @@ static inline void print_stack_overflow(void) { }
 
 static void call_on_stack(void *func, void *stack)
 {
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=b" (stack)
-		     : "0" (stack),
-		       [thunk_target] "D"(func)
+		     "movl %[sp], %%esp"
+		     : [sp] "+b" (stack)
+		     : [thunk_target] "D" (func)
 		     : "memory", "cc", "edx", "ecx", "eax");
 }
 
@@ -71,7 +70,7 @@ static inline void *current_stack(void)
 static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
-	u32 *isp, *prev_esp, arg1;
+	u32 *isp, *prev_esp;
 
 	curstk = (struct irq_stack *) current_stack();
 	irqstk = __this_cpu_read(pcpu_hot.hardirq_stack_ptr);
@@ -94,12 +93,11 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	if (unlikely(overflow))
 		call_on_stack(print_stack_overflow, isp);
 
-	asm volatile("xchgl	%%ebx,%%esp	\n"
+	asm volatile("xchgl %[sp], %%esp\n"
 		     CALL_NOSPEC
-		     "movl	%%ebx,%%esp	\n"
-		     : "=a" (arg1), "=b" (isp)
-		     :  "0" (desc),   "1" (isp),
-			[thunk_target] "D" (desc->handle_irq)
+		     "movl %[sp], %%esp"
+		     : "+a" (desc), [sp] "+b" (isp)
+		     : [thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "ecx");
 	return 1;
 }

[tip: x86/asm] x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     d4432fb5b8798a7663974bed277a8a6e330a50d8
Gitweb:        https://git.kernel.org/tip/d4432fb5b8798a7663974bed277a8a6e330a50d8
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:24 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:28:58 +01:00

x86/irq/32: Use current_stack_pointer to avoid asm() in check_stack_overflow()

Make code more readable by using the 'current_stack_pointer' global variable.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-4-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index eab4580..8c7babb 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -31,10 +31,7 @@ int sysctl_panic_on_stackoverflow __read_mostly;
 /* Debugging check for stack overflow: is there less than 1KB free? */
 static int check_stack_overflow(void)
 {
-	long sp;
-
-	__asm__ __volatile__("andl %%esp,%0" :
-			     "=r" (sp) : "0" (THREAD_SIZE - 1));
+	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
 	return sp < (sizeof(struct thread_info) + STACK_WARN);
 }

[tip: x86/asm] x86/irq/32: Change some static functions to bool

[tip-bot2 for Uros Bizjak]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     c8b584fe82d0f1e478a598f954943b095a4a8f5c
Gitweb:        https://git.kernel.org/tip/c8b584fe82d0f1e478a598f954943b095a4a8f5c
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 03 Mar 2025 16:54:25 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 04 Mar 2025 20:28:58 +01:00

x86/irq/32: Change some static functions to bool

The return values of these functions is 0/1, but they use an int
type instead of bool:

  check_stack_overflow()
  execute_on_irq_stack()

Change the type of these function to bool and adjust their return
values and affected helper variables.

[ mingo: Rewrote the changelog ]

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303155446.112769-5-ubizjak@gmail.com
---
 arch/x86/kernel/irq_32.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 8c7babb..d301208 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -29,7 +29,7 @@
 int sysctl_panic_on_stackoverflow __read_mostly;
 
 /* Debugging check for stack overflow: is there less than 1KB free? */
-static int check_stack_overflow(void)
+static bool check_stack_overflow(void)
 {
 	unsigned long sp = current_stack_pointer & (THREAD_SIZE - 1);
 
@@ -45,7 +45,7 @@ static void print_stack_overflow(void)
 }
 
 #else
-static inline int check_stack_overflow(void) { return 0; }
+static inline bool check_stack_overflow(void) { return false; }
 static inline void print_stack_overflow(void) { }
 #endif
 
@@ -64,7 +64,7 @@ static inline void *current_stack(void)
 	return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1));
 }
 
-static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
+static inline bool execute_on_irq_stack(bool overflow, struct irq_desc *desc)
 {
 	struct irq_stack *curstk, *irqstk;
 	u32 *isp, *prev_esp;
@@ -79,7 +79,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (unlikely(curstk == irqstk))
-		return 0;
+		return false;
 
 	isp = (u32 *) ((char *)irqstk + sizeof(*irqstk));
 
@@ -96,7 +96,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
 		     : "+a" (desc), [sp] "+b" (isp)
 		     : [thunk_target] "D" (desc->handle_irq)
 		     : "memory", "cc", "edx", "ecx");
-	return 1;
+	return true;
 }
 
 /*
@@ -145,7 +145,7 @@ void do_softirq_own_stack(void)
 
 void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
-	int overflow = check_stack_overflow();
+	bool overflow = check_stack_overflow();
 
 	if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) {
 		if (unlikely(overflow))