[PATCH] init: consolidate trap_init()

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.

Signed-off-by: Jisheng Zhang <redacted>
---
 arch/arc/kernel/traps.c      |  5 -----
 arch/arm/kernel/traps.c      |  5 -----
 arch/h8300/kernel/traps.c    | 13 -------------
 arch/hexagon/kernel/traps.c  |  4 ----
 arch/nds32/kernel/traps.c    |  5 -----
 arch/nios2/kernel/traps.c    |  5 -----
 arch/openrisc/kernel/traps.c |  5 -----
 arch/parisc/kernel/traps.c   |  4 ----
 arch/powerpc/kernel/traps.c  |  5 -----
 arch/riscv/kernel/traps.c    |  5 -----
 arch/um/kernel/trap.c        |  4 ----
 init/main.c                  |  2 ++
 12 files changed, 2 insertions(+), 60 deletions(-)

diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
index 57235e5c0cea..6b83e3f2b41c 100644
--- a/arch/arc/kernel/traps.c
+++ b/arch/arc/kernel/traps.c

@@ -20,11 +20,6 @@
 #include <asm/unaligned.h>
 #include <asm/kprobes.h>
 
-void __init trap_init(void)
-{
-	return;
-}
-
 void die(const char *str, struct pt_regs *regs, unsigned long address)
 {
 	show_kernel_fault_diag(str, regs, address);

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 17d5a785df28..9baccef20392 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c

@@ -780,11 +780,6 @@ void abort(void)
 	panic("Oops failed to kill thread");
 }
 
-void __init trap_init(void)
-{
-	return;
-}
-
 #ifdef CONFIG_KUSER_HELPERS
 static void __init kuser_init(void *vectors)
 {

diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c
index 5d8b969cd8f3..c3a3ebf77fbb 100644
--- a/arch/h8300/kernel/traps.c
+++ b/arch/h8300/kernel/traps.c

@@ -30,19 +30,6 @@
 
 static DEFINE_SPINLOCK(die_lock);
 
-/*
- * this must be called very early as the kernel might
- * use some instruction that are emulated on the 060
- */
-
-void __init base_trap_init(void)
-{
-}
-
-void __init trap_init(void)
-{
-}
-
 asmlinkage void set_esp0(unsigned long ssp)
 {
 	current->thread.esp0 = ssp;

diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index 904134b37232..edfc35dafeb1 100644
--- a/arch/hexagon/kernel/traps.c
+++ b/arch/hexagon/kernel/traps.c

@@ -28,10 +28,6 @@
 #define TRAP_SYSCALL	1
 #define TRAP_DEBUG	0xdb
 
-void __init trap_init(void)
-{
-}
-
 #ifdef CONFIG_GENERIC_BUG
 /* Maybe should resemble arch/sh/kernel/traps.c ?? */
 int is_valid_bugaddr(unsigned long addr)

diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index ee0d9ae192a5..f06421c645af 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c

@@ -183,11 +183,6 @@ void __pgd_error(const char *file, int line, unsigned long val)
 }
 
 extern char *exception_vector, *exception_vector_end;
-void __init trap_init(void)
-{
-	return;
-}
-
 void __init early_trap_init(void)
 {
 	unsigned long ivb = 0;

diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
index b172da4eb1a9..596986a74a26 100644
--- a/arch/nios2/kernel/traps.c
+++ b/arch/nios2/kernel/traps.c

@@ -105,11 +105,6 @@ void show_stack(struct task_struct *task, unsigned long *stack,
 	printk("%s\n", loglvl);
 }
 
-void __init trap_init(void)
-{
-	/* Nothing to do here */
-}
-
 /* Breakpoint handler */
 asmlinkage void breakpoint_c(struct pt_regs *fp)
 {

diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index 4d61333c2623..aa1e709405ac 100644
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c

@@ -231,11 +231,6 @@ void unhandled_exception(struct pt_regs *regs, int ea, int vector)
 	die("Oops", regs, 9);
 }
 
-void __init trap_init(void)
-{
-	/* Nothing needs to be done */
-}
-
 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
 {
 	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);

diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 8d8441d4562a..747c328fb886 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c

@@ -859,7 +859,3 @@ void  __init early_trap_init(void)
 
 	initialize_ivt(&fault_vector_20);
 }
-
-void __init trap_init(void)
-{
-}

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index a44a30b0688c..e952bee89684 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c

@@ -2207,11 +2207,6 @@ DEFINE_INTERRUPT_HANDLER(kernel_bad_stack)
 	die("Bad kernel stack pointer", regs, SIGABRT);
 }
 
-void __init trap_init(void)
-{
-}
-
-
 #ifdef CONFIG_PPC_EMULATED_STATS
 
 #define WARN_EMULATED_SETUP(type)	.type = { .name = #type }

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 0879b5df11b9..b3f3d84de779 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c

@@ -194,8 +194,3 @@ int is_valid_bugaddr(unsigned long pc)
 		return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
 }
 #endif /* CONFIG_GENERIC_BUG */
-
-/* stvec & scratch is already set from head.S */
-void trap_init(void)
-{
-}

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index ad12f78bda7e..3198c4767387 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c

@@ -311,7 +311,3 @@ void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	do_IRQ(WINCH_IRQ, regs);
 }
-
-void trap_init(void)
-{
-}

diff --git a/init/main.c b/init/main.c
index 53b278845b88..4bdbe2928530 100644
--- a/init/main.c
+++ b/init/main.c

@@ -790,6 +790,8 @@ static inline void initcall_debug_enable(void)
 }
 #endif
 
+void __init __weak trap_init(void) { }
+
 /* Report memory auto-initialization states for this boot. */
 static void __init report_meminit(void)
 {

-- 
2.31.0

Le 14/04/2021 à 10:58, Jisheng Zhang a écrit :

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.

You define the weak function in the __init section.

Most but not all architectures had it in __init section.

And the remaining ones may not be defined in __init section. For instance look at the one in alpha 
architecture.

Have you checked that it is not a problem ? It would be good to say something about it in the commit 
description.

I think in a C file we don't try to save space as much as in a header file.

I would prefer something like:


void __init __weak trap_init(void)
{
}

  /* Report memory auto-initialization states for this boot. */
  static void __init report_meminit(void)
  {

On Wed, 14 Apr 2021 11:10:42 +0200
Christophe Leroy [off-list ref] wrote:

Le 14/04/2021 à 10:58, Jisheng Zhang a écrit :

quoted

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.  

You define the weak function in the __init section.

Most but not all architectures had it in __init section.

And the remaining ones may not be defined in __init section. For instance look at the one in alpha
architecture.

Have you checked that it is not a problem ? It would be good to say something about it in the commit
description.

For those non-nop platforms, I can only test x86/arm64/, but both has
__init mark. I'm not sure whether this is a problem for alpha etc. Maybe
I can check which section the trap_init() sits. Or to avoid any possible
regression, I can add __init mark to those remaining ones without it in
preparation patches.

quoted

Signed-off-by: Jisheng Zhang <redacted>
---
  arch/arc/kernel/traps.c      |  5 -----
  arch/arm/kernel/traps.c      |  5 -----
  arch/h8300/kernel/traps.c    | 13 -------------
  arch/hexagon/kernel/traps.c  |  4 ----
  arch/nds32/kernel/traps.c    |  5 -----
  arch/nios2/kernel/traps.c    |  5 -----
  arch/openrisc/kernel/traps.c |  5 -----
  arch/parisc/kernel/traps.c   |  4 ----
  arch/powerpc/kernel/traps.c  |  5 -----
  arch/riscv/kernel/traps.c    |  5 -----
  arch/um/kernel/trap.c        |  4 ----
  init/main.c                  |  2 ++
  12 files changed, 2 insertions(+), 60 deletions(-)

diff --git a/init/main.c b/init/main.c
index 53b278845b88..4bdbe2928530 100644
--- a/init/main.c
+++ b/init/main.c

@@ -790,6 +790,8 @@ static inline void initcall_debug_enable(void)
  }
  #endif

+void __init __weak trap_init(void) { }
+  

I think in a C file we don't try to save space as much as in a header file.

This is to follow most weak NOP implementations in init/main.c to make
the style unified in the same file. I'm not sure which is better.

I would prefer something like:


void __init __weak trap_init(void)
{
}

quoted

  /* Report memory auto-initialization states for this boot. */
  static void __init report_meminit(void)
  {
 

On Wed, 14 Apr 2021 17:27:57 +0800
Jisheng Zhang [off-list ref] wrote:

CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe.


On Wed, 14 Apr 2021 11:10:42 +0200
Christophe Leroy [off-list ref] wrote:

quoted

Le 14/04/2021 à 10:58, Jisheng Zhang a écrit :  

quoted

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.  

You define the weak function in the __init section.

Most but not all architectures had it in __init section.

And the remaining ones may not be defined in __init section. For instance look at the one in alpha
architecture.

Have you checked that it is not a problem ? It would be good to say something about it in the commit
description.  

For those non-nop platforms, I can only test x86/arm64/, but both has
__init mark. I'm not sure whether this is a problem for alpha etc. Maybe
I can check which section the trap_init() sits. Or to avoid any possible
regression, I can add __init mark to those remaining ones without it in
preparation patches.

Hi,

I found only three platforms don't have the __init marker for trap_init(), I
will add the __init marker in three preparation patches in new version.

thanks

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.

The alpha, microblaze and sparc32 have real trap_init() implementation
but the __init marker is missing, so add it to these three platforms.

Signed-off-by: Jisheng Zhang <redacted>
---
Since v1:
 - add __init marker to trap_init() for alpha, microblaze and sparc32
 - adjust the generic weak NOP trap_init() location to make it sits with
   other NOP implementations together

 arch/alpha/kernel/traps.c      |  2 +-
 arch/arc/kernel/traps.c        |  5 -----
 arch/arm/kernel/traps.c        |  5 -----
 arch/h8300/kernel/traps.c      | 13 -------------
 arch/hexagon/kernel/traps.c    |  4 ----
 arch/microblaze/kernel/traps.c |  2 +-
 arch/nds32/kernel/traps.c      |  5 -----
 arch/nios2/kernel/traps.c      |  5 -----
 arch/openrisc/kernel/traps.c   |  5 -----
 arch/parisc/kernel/traps.c     |  4 ----
 arch/powerpc/kernel/traps.c    |  5 -----
 arch/riscv/kernel/traps.c      |  5 -----
 arch/sparc/kernel/traps_32.c   |  2 +-
 arch/um/kernel/trap.c          |  4 ----
 init/main.c                    |  2 ++
 15 files changed, 5 insertions(+), 63 deletions(-)

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 921d4b6e4d95..96b203199c6c 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c

@@ -973,7 +973,7 @@ do_entUnaUser(void __user * va, unsigned long opcode,
 	return;
 }
 
-void
+void __init
 trap_init(void)
 {
 	/* Tell PAL-code what global pointer we want in the kernel.  */

diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
index 57235e5c0cea..6b83e3f2b41c 100644
--- a/arch/arc/kernel/traps.c
+++ b/arch/arc/kernel/traps.c

@@ -20,11 +20,6 @@
 #include <asm/unaligned.h>
 #include <asm/kprobes.h>
 
-void __init trap_init(void)
-{
-	return;
-}
-
 void die(const char *str, struct pt_regs *regs, unsigned long address)
 {
 	show_kernel_fault_diag(str, regs, address);

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 17d5a785df28..9baccef20392 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c

@@ -780,11 +780,6 @@ void abort(void)
 	panic("Oops failed to kill thread");
 }
 
-void __init trap_init(void)
-{
-	return;
-}
-
 #ifdef CONFIG_KUSER_HELPERS
 static void __init kuser_init(void *vectors)
 {

diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c
index 5d8b969cd8f3..c3a3ebf77fbb 100644
--- a/arch/h8300/kernel/traps.c
+++ b/arch/h8300/kernel/traps.c

@@ -30,19 +30,6 @@
 
 static DEFINE_SPINLOCK(die_lock);
 
-/*
- * this must be called very early as the kernel might
- * use some instruction that are emulated on the 060
- */
-
-void __init base_trap_init(void)
-{
-}
-
-void __init trap_init(void)
-{
-}
-
 asmlinkage void set_esp0(unsigned long ssp)
 {
 	current->thread.esp0 = ssp;

diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index 904134b37232..edfc35dafeb1 100644
--- a/arch/hexagon/kernel/traps.c
+++ b/arch/hexagon/kernel/traps.c

@@ -28,10 +28,6 @@
 #define TRAP_SYSCALL	1
 #define TRAP_DEBUG	0xdb
 
-void __init trap_init(void)
-{
-}
-
 #ifdef CONFIG_GENERIC_BUG
 /* Maybe should resemble arch/sh/kernel/traps.c ?? */
 int is_valid_bugaddr(unsigned long addr)

diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c
index 94b6fe93147d..7c15704fe56e 100644
--- a/arch/microblaze/kernel/traps.c
+++ b/arch/microblaze/kernel/traps.c

@@ -18,7 +18,7 @@
 #include <asm/exceptions.h>
 #include <asm/unwind.h>
 
-void trap_init(void)
+void __init trap_init(void)
 {
 	__enable_hw_exceptions();
 }

diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index ee0d9ae192a5..f06421c645af 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c

@@ -183,11 +183,6 @@ void __pgd_error(const char *file, int line, unsigned long val)
 }
 
 extern char *exception_vector, *exception_vector_end;
-void __init trap_init(void)
-{
-	return;
-}
-
 void __init early_trap_init(void)
 {
 	unsigned long ivb = 0;

diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
index b172da4eb1a9..596986a74a26 100644
--- a/arch/nios2/kernel/traps.c
+++ b/arch/nios2/kernel/traps.c

@@ -105,11 +105,6 @@ void show_stack(struct task_struct *task, unsigned long *stack,
 	printk("%s\n", loglvl);
 }
 
-void __init trap_init(void)
-{
-	/* Nothing to do here */
-}
-
 /* Breakpoint handler */
 asmlinkage void breakpoint_c(struct pt_regs *fp)
 {

diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index 4d61333c2623..aa1e709405ac 100644
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c

@@ -231,11 +231,6 @@ void unhandled_exception(struct pt_regs *regs, int ea, int vector)
 	die("Oops", regs, 9);
 }
 
-void __init trap_init(void)
-{
-	/* Nothing needs to be done */
-}
-
 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
 {
 	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);

diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 8d8441d4562a..747c328fb886 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c

@@ -859,7 +859,3 @@ void  __init early_trap_init(void)
 
 	initialize_ivt(&fault_vector_20);
 }
-
-void __init trap_init(void)
-{
-}

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index a44a30b0688c..e952bee89684 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c

@@ -2207,11 +2207,6 @@ DEFINE_INTERRUPT_HANDLER(kernel_bad_stack)
 	die("Bad kernel stack pointer", regs, SIGABRT);
 }
 
-void __init trap_init(void)
-{
-}
-
-
 #ifdef CONFIG_PPC_EMULATED_STATS
 
 #define WARN_EMULATED_SETUP(type)	.type = { .name = #type }

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 0879b5df11b9..b3f3d84de779 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c

@@ -194,8 +194,3 @@ int is_valid_bugaddr(unsigned long pc)
 		return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
 }
 #endif /* CONFIG_GENERIC_BUG */
-
-/* stvec & scratch is already set from head.S */
-void trap_init(void)
-{
-}

diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 247a0d9683b2..c4df20ec01e2 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c

@@ -365,7 +365,7 @@ EXPORT_SYMBOL(do_BUG);
  * up here so that timer interrupts work during initialization.
  */
 
-void trap_init(void)
+void __init trap_init(void)
 {
 	extern void thread_info_offsets_are_bolixed_pete(void);
 

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index ad12f78bda7e..3198c4767387 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c

@@ -311,7 +311,3 @@ void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	do_IRQ(WINCH_IRQ, regs);
 }
-
-void trap_init(void)
-{
-}

diff --git a/init/main.c b/init/main.c
index 53b278845b88..8d14674c4e00 100644
--- a/init/main.c
+++ b/init/main.c

@@ -779,6 +779,8 @@ void __init __weak poking_init(void) { }
 
 void __init __weak pgtable_cache_init(void) { }
 
+void __init __weak trap_init(void) { }
+
 bool initcall_debug;
 core_param(initcall_debug, initcall_debug, bool, 0644);
 

-- 
2.31.0

On 4/14/21 12:00 PM, Jisheng Zhang wrote:

Many architectures implement the trap_init() as NOP, since there is
no such default for trap_init(), this empty stub is duplicated among
these architectures. Provide a generic but weak NOP implementation
to drop the empty stubs of trap_init() in these architectures.

The alpha, microblaze and sparc32 have real trap_init() implementation
but the __init marker is missing, so add it to these three platforms.

Signed-off-by: Jisheng Zhang <redacted>
---
Since v1:
  - add __init marker to trap_init() for alpha, microblaze and sparc32
  - adjust the generic weak NOP trap_init() location to make it sits with
    other NOP implementations together

  arch/alpha/kernel/traps.c      |  2 +-
  arch/arc/kernel/traps.c        |  5 -----
  arch/arm/kernel/traps.c        |  5 -----
  arch/h8300/kernel/traps.c      | 13 -------------
  arch/hexagon/kernel/traps.c    |  4 ----
  arch/microblaze/kernel/traps.c |  2 +-
  arch/nds32/kernel/traps.c      |  5 -----
  arch/nios2/kernel/traps.c      |  5 -----
  arch/openrisc/kernel/traps.c   |  5 -----
  arch/parisc/kernel/traps.c     |  4 ----
  arch/powerpc/kernel/traps.c    |  5 -----
  arch/riscv/kernel/traps.c      |  5 -----
  arch/sparc/kernel/traps_32.c   |  2 +-
  arch/um/kernel/trap.c          |  4 ----
  init/main.c                    |  2 ++
  15 files changed, 5 insertions(+), 63 deletions(-)

For parisc:

Acked-by: Helge Deller <deller@gmx.de> # parisc

Thanks!
Helge