[RFC,27/28] ARM: entry: Add FIQ/NMI C callbacks

Commit Message

Linus Walleij Oct. 10, 2024, 11:34 a.m. UTC

These NMI (FIQ) callbacks are added to complete the calls expected
by the generic entry. They are perfectly fine to add code to
but are left empty for now.

Signed-off-by: Linus Walleij <[e-mail]>
---
 arch/arm/include/asm/entry.h   |  4 ++++
 arch/arm/kernel/entry-armv.S   | 14 +++++++++++---
 arch/arm/kernel/entry-header.S |  2 ++
 arch/arm/kernel/entry.c        | 16 ++++++++++++++++
 4 files changed, 33 insertions(+), 3 deletions(-)

Patch

diff --git a/arch/arm/include/asm/entry.h b/arch/arm/include/asm/entry.h
index a78bc5054b09..2e7ccd87f0eb 100644
--- a/arch/arm/include/asm/entry.h
+++ b/arch/arm/include/asm/entry.h
@@ -14,5 +14,9 @@  void irqentry_enter_from_user_mode(struct pt_regs *regs);
 void irqentry_exit_to_user_mode(struct pt_regs *regs);
 void irqentry_enter_from_kernel_mode(struct pt_regs *regs);
 void irqentry_exit_to_kernel_mode(struct pt_regs *regs);
+void irqentry_nmi_enter_from_user_mode(struct pt_regs *regs);
+void irqentry_nmi_exit_to_user_mode(struct pt_regs *regs);
+void irqentry_nmi_enter_from_kernel_mode(struct pt_regs *regs);
+void irqentry_nmi_exit_to_kernel_mode(struct pt_regs *regs);
 
 #endif /* __ASM_ENTRY_H__ */
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 600375f6f5d8..839f3ebe7228 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -157,7 +157,7 @@  ENDPROC(__und_invalid)
 #define SPFIX(code...)
 #endif
 
-	.macro	svc_entry, stack_hole=0 uaccess=1, overflow_check=1
+	.macro	svc_entry, stack_hole=0 uaccess=1, overflow_check=1, nmi=0
  UNWIND(.fnstart		)
 	sub	sp, sp, #(SVC_REGS_SIZE + \stack_hole)
  THUMB(	add	sp, r1		)	@ get SP in a GPR without
@@ -205,7 +205,11 @@  ENDPROC(__und_invalid)
 	uaccess_entry tsk, r0, r1, r2, \uaccess
 
 	mov	r0, sp				@ 'regs'
+	.if \nmi
+	bl	irqentry_nmi_enter_from_kernel_mode
+	.else
 	bl	irqentry_enter_from_kernel_mode
+	.endif
 
 	.endm
 
@@ -297,7 +301,7 @@  ENDPROC(__pabt_svc)
 
 	.align	5
 __fiq_svc:
-	svc_entry
+	svc_entry nmi=1
 	mov	r0, sp				@ struct pt_regs *regs
 	bl	handle_fiq_as_nmi
 	svc_exit_via_fiq
@@ -315,7 +319,7 @@  ENDPROC(__fiq_svc)
 @
 	.align 5
 __fiq_abt:
-	svc_entry
+	svc_entry nmi=1
 
  ARM(	msr	cpsr_c, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
  THUMB( mov	r0, #ABT_MODE | PSR_I_BIT | PSR_F_BIT )
@@ -490,9 +494,13 @@  ENDPROC(ret_from_exception)
 	.align	5
 __fiq_usr:
 	usr_entry
+	mov	r0, sp
+	bl	irqentry_nmi_enter_from_user_mode
 	kuser_cmpxchg_check
 	mov	r0, sp				@ struct pt_regs *regs
 	bl	handle_fiq_as_nmi
+	mov	r0, sp
+	bl	irqentry_nmi_exit_to_user_mode
 	get_thread_info tsk
 	restore_user_regs
  UNWIND(.fnend		)
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index cfaf14d71378..ec8a6e193802 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -252,6 +252,8 @@ 
 	@
 	.macro  svc_exit_via_fiq
 	uaccess_exit tsk, r0, r1
+	mov	r0, sp
+	bl	irqentry_nmi_exit_to_kernel_mode
 #ifndef CONFIG_THUMB2_KERNEL
 	@ ARM mode restore
 	mov	r0, sp
diff --git a/arch/arm/kernel/entry.c b/arch/arm/kernel/entry.c
index 1e1284cc4cae..09109215dfdf 100644
--- a/arch/arm/kernel/entry.c
+++ b/arch/arm/kernel/entry.c
@@ -69,3 +69,19 @@  noinstr void irqentry_exit_to_kernel_mode(struct pt_regs *regs)
 	else
 		trace_hardirqs_off();
 }
+
+noinstr void irqentry_nmi_enter_from_user_mode(struct pt_regs *regs)
+{
+}
+
+noinstr void irqentry_nmi_exit_to_user_mode(struct pt_regs *regs)
+{
+}
+
+noinstr void irqentry_nmi_enter_from_kernel_mode(struct pt_regs *regs)
+{
+}
+
+noinstr void irqentry_nmi_exit_to_kernel_mode(struct pt_regs *regs)
+{
+}