[PATCH] x86: unify extable_{32|64}.c

[PATCH] x86: unify extable_{32|64}.c

[Harvey Harrison]

Introduce fixup_exception() on X86_64 and use it in kprobes to
eliminate an #ifdef.

Only X86_64 needs search_extable() due to a stepping bug.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
 arch/x86/kernel/kprobes.c |   12 +--------
 arch/x86/mm/Makefile_32   |    2 +-
 arch/x86/mm/Makefile_64   |    2 +-
 arch/x86/mm/extable.c     |   62 +++++++++++++++++++++++++++++++++++++++++++++
 arch/x86/mm/extable_32.c  |   35 -------------------------
 arch/x86/mm/extable_64.c  |   34 ------------------------
 6 files changed, 65 insertions(+), 82 deletions(-)

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 1a0d96d..045a45e 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -902,19 +902,9 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 		 * In case the user-specified fault handler returned
 		 * zero, try to fix up.
 		 */
-#ifdef CONFIG_X86_64
-		{
-			const struct exception_table_entry *fixup;
-			fixup = search_exception_tables(regs->ip);
-			if (fixup) {
-				regs->ip = fixup->fixup;
-				return 1;
-			}
-		}
-#else
 		if (fixup_exception(regs))
 			return 1;
-#endif
+
 		/*
 		 * fixup routine could not handle it,
 		 * Let do_page_fault() fix it.
diff --git a/arch/x86/mm/Makefile_32 b/arch/x86/mm/Makefile_32
index a01aca7..6a5e981 100644
--- a/arch/x86/mm/Makefile_32
+++ b/arch/x86/mm/Makefile_32
@@ -2,7 +2,7 @@
 # Makefile for the linux i386-specific parts of the memory manager.
 #
 
-obj-y	:= init_32.o pgtable_32.o fault_32.o ioremap_32.o extable_32.o pageattr_32.o mmap.o
+obj-y	:= init_32.o pgtable_32.o fault_32.o ioremap_32.o extable.o pageattr_32.o mmap.o
 
 obj-$(CONFIG_NUMA) += discontig_32.o
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
diff --git a/arch/x86/mm/Makefile_64 b/arch/x86/mm/Makefile_64
index b5a7448..09c997f 100644
--- a/arch/x86/mm/Makefile_64
+++ b/arch/x86/mm/Makefile_64
@@ -2,7 +2,7 @@
 # Makefile for the linux x86_64-specific parts of the memory manager.
 #
 
-obj-y	 := init_64.o fault_64.o ioremap_64.o extable_64.o pageattr_64.o mmap.o
+obj-y	 := init_64.o fault_64.o ioremap_64.o extable.o pageattr_64.o mmap.o
 obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
 obj-$(CONFIG_NUMA) += numa_64.o
 obj-$(CONFIG_K8_NUMA) += k8topology_64.o
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
new file mode 100644
index 0000000..7e8db53
--- /dev/null
+++ b/arch/x86/mm/extable.c
@@ -0,0 +1,62 @@
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/uaccess.h>
+
+
+int fixup_exception(struct pt_regs *regs)
+{
+	const struct exception_table_entry *fixup;
+
+#ifdef CONFIG_PNPBIOS
+	if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
+		extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
+		extern u32 pnp_bios_is_utter_crap;
+		pnp_bios_is_utter_crap = 1;
+		printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
+		__asm__ volatile(
+			"movl %0, %%esp\n\t"
+			"jmp *%1\n\t"
+			: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
+		panic("do_trap: can't hit this");
+	}
+#endif
+
+	fixup = search_exception_tables(regs->ip);
+	if (fixup) {
+		regs->ip = fixup->fixup;
+		return 1;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_X86_64
+/*
+ * Need to defined our own search_extable on X86_64 to work around
+ * a B stepping K8 bug.
+ */
+const struct exception_table_entry *
+search_extable(const struct exception_table_entry *first,
+	       const struct exception_table_entry *last,
+	       unsigned long value)
+{
+	/* B stepping K8 bug */
+	if ((value >> 32) == 0)
+		value |= 0xffffffffUL << 32;
+
+	while (first <= last) {
+		const struct exception_table_entry *mid;
+		long diff;
+
+		mid = (last - first) / 2 + first;
+		diff = mid->insn - value;
+		if (diff == 0)
+			return mid;
+		else if (diff < 0)
+			first = mid+1;
+		else
+			last = mid-1;
+	}
+	return NULL;
+}
+#endif
diff --git a/arch/x86/mm/extable_32.c b/arch/x86/mm/extable_32.c
deleted file mode 100644
index 4168546..0000000
--- a/arch/x86/mm/extable_32.c
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- * linux/arch/i386/mm/extable.c
- */
-
-#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <asm/uaccess.h>
-
-int fixup_exception(struct pt_regs *regs)
-{
-	const struct exception_table_entry *fixup;
-
-#ifdef CONFIG_PNPBIOS
-	if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs)))
-	{
-		extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
-		extern u32 pnp_bios_is_utter_crap;
-		pnp_bios_is_utter_crap = 1;
-		printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
-		__asm__ volatile(
-			"movl %0, %%esp\n\t"
-			"jmp *%1\n\t"
-			: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
-		panic("do_trap: can't hit this");
-	}
-#endif
-
-	fixup = search_exception_tables(regs->ip);
-	if (fixup) {
-		regs->ip = fixup->fixup;
-		return 1;
-	}
-
-	return 0;
-}
diff --git a/arch/x86/mm/extable_64.c b/arch/x86/mm/extable_64.c
deleted file mode 100644
index 79ac6e7..0000000
--- a/arch/x86/mm/extable_64.c
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * linux/arch/x86_64/mm/extable.c
- */
-
-#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <linux/init.h>
-#include <asm/uaccess.h>
-
-/* Simple binary search */
-const struct exception_table_entry *
-search_extable(const struct exception_table_entry *first,
-	       const struct exception_table_entry *last,
-	       unsigned long value)
-{
-	/* Work around a B stepping K8 bug */
-	if ((value >> 32) == 0)
-		value |= 0xffffffffUL << 32; 
-
-        while (first <= last) {
-		const struct exception_table_entry *mid;
-		long diff;
-
-		mid = (last - first) / 2 + first;
-		diff = mid->insn - value;
-                if (diff == 0)
-                        return mid;
-                else if (diff < 0)
-                        first = mid+1;
-                else
-                        last = mid-1;
-        }
-        return NULL;
-}
-- 
1.5.4.rc0.1143.g1a8a

Re: [PATCH] x86: unify extable_{32|64}.c

[Ingo Molnar]

* Harvey Harrison <harvey.harrison@gmail.com> wrote:

> Introduce fixup_exception() on X86_64 and use it in kprobes to 
> eliminate an #ifdef.
> 
> Only X86_64 needs search_extable() due to a stepping bug.

thanks, applied.

	Ingo

Re: [PATCH] x86: unify extable_{32|64}.c

[Masami Hiramatsu]

Hi Harvey,

Harvey Harrison wrote:
> Introduce fixup_exception() on X86_64 and use it in kprobes to
> eliminate an #ifdef.
> 
> Only X86_64 needs search_extable() due to a stepping bug.

It's a good work!
If you can work on it, please add a prototype declaration of
fixup_exception() in asm-x86/uaccess_64.h too.

> 
> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
> ---
>  arch/x86/kernel/kprobes.c |   12 +--------
>  arch/x86/mm/Makefile_32   |    2 +-
>  arch/x86/mm/Makefile_64   |    2 +-
>  arch/x86/mm/extable.c     |   62 +++++++++++++++++++++++++++++++++++++++++++++
>  arch/x86/mm/extable_32.c  |   35 -------------------------
>  arch/x86/mm/extable_64.c  |   34 ------------------------
>  6 files changed, 65 insertions(+), 82 deletions(-)
> 
> diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
> index 1a0d96d..045a45e 100644
> --- a/arch/x86/kernel/kprobes.c
> +++ b/arch/x86/kernel/kprobes.c
> @@ -902,19 +902,9 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
>  		 * In case the user-specified fault handler returned
>  		 * zero, try to fix up.
>  		 */
> -#ifdef CONFIG_X86_64
> -		{
> -			const struct exception_table_entry *fixup;
> -			fixup = search_exception_tables(regs->ip);
> -			if (fixup) {
> -				regs->ip = fixup->fixup;
> -				return 1;
> -			}
> -		}
> -#else
>  		if (fixup_exception(regs))
>  			return 1;
> -#endif
> +
>  		/*
>  		 * fixup routine could not handle it,
>  		 * Let do_page_fault() fix it.
> diff --git a/arch/x86/mm/Makefile_32 b/arch/x86/mm/Makefile_32
> index a01aca7..6a5e981 100644
> --- a/arch/x86/mm/Makefile_32
> +++ b/arch/x86/mm/Makefile_32
> @@ -2,7 +2,7 @@
>  # Makefile for the linux i386-specific parts of the memory manager.
>  #
>  
> -obj-y	:= init_32.o pgtable_32.o fault_32.o ioremap_32.o extable_32.o pageattr_32.o mmap.o
> +obj-y	:= init_32.o pgtable_32.o fault_32.o ioremap_32.o extable.o pageattr_32.o mmap.o
>  
>  obj-$(CONFIG_NUMA) += discontig_32.o
>  obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
> diff --git a/arch/x86/mm/Makefile_64 b/arch/x86/mm/Makefile_64
> index b5a7448..09c997f 100644
> --- a/arch/x86/mm/Makefile_64
> +++ b/arch/x86/mm/Makefile_64
> @@ -2,7 +2,7 @@
>  # Makefile for the linux x86_64-specific parts of the memory manager.
>  #
>  
> -obj-y	 := init_64.o fault_64.o ioremap_64.o extable_64.o pageattr_64.o mmap.o
> +obj-y	 := init_64.o fault_64.o ioremap_64.o extable.o pageattr_64.o mmap.o
>  obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
>  obj-$(CONFIG_NUMA) += numa_64.o
>  obj-$(CONFIG_K8_NUMA) += k8topology_64.o
> diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
> new file mode 100644
> index 0000000..7e8db53
> --- /dev/null
> +++ b/arch/x86/mm/extable.c
> @@ -0,0 +1,62 @@
> +#include <linux/module.h>
> +#include <linux/spinlock.h>
> +#include <asm/uaccess.h>
> +
> +
> +int fixup_exception(struct pt_regs *regs)
> +{
> +	const struct exception_table_entry *fixup;
> +
> +#ifdef CONFIG_PNPBIOS
> +	if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
> +		extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
> +		extern u32 pnp_bios_is_utter_crap;
> +		pnp_bios_is_utter_crap = 1;
> +		printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
> +		__asm__ volatile(
> +			"movl %0, %%esp\n\t"
> +			"jmp *%1\n\t"
> +			: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
> +		panic("do_trap: can't hit this");
> +	}
> +#endif
> +
> +	fixup = search_exception_tables(regs->ip);
> +	if (fixup) {
> +		regs->ip = fixup->fixup;
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_X86_64
> +/*
> + * Need to defined our own search_extable on X86_64 to work around
> + * a B stepping K8 bug.
> + */
> +const struct exception_table_entry *
> +search_extable(const struct exception_table_entry *first,
> +	       const struct exception_table_entry *last,
> +	       unsigned long value)
> +{
> +	/* B stepping K8 bug */
> +	if ((value >> 32) == 0)
> +		value |= 0xffffffffUL << 32;
> +
> +	while (first <= last) {
> +		const struct exception_table_entry *mid;
> +		long diff;
> +
> +		mid = (last - first) / 2 + first;
> +		diff = mid->insn - value;
> +		if (diff == 0)
> +			return mid;
> +		else if (diff < 0)
> +			first = mid+1;
> +		else
> +			last = mid-1;
> +	}
> +	return NULL;
> +}
> +#endif
> diff --git a/arch/x86/mm/extable_32.c b/arch/x86/mm/extable_32.c
> deleted file mode 100644
> index 4168546..0000000
> --- a/arch/x86/mm/extable_32.c
> +++ /dev/null
> @@ -1,35 +0,0 @@
> -/*
> - * linux/arch/i386/mm/extable.c
> - */
> -
> -#include <linux/module.h>
> -#include <linux/spinlock.h>
> -#include <asm/uaccess.h>
> -
> -int fixup_exception(struct pt_regs *regs)
> -{
> -	const struct exception_table_entry *fixup;
> -
> -#ifdef CONFIG_PNPBIOS
> -	if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs)))
> -	{
> -		extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
> -		extern u32 pnp_bios_is_utter_crap;
> -		pnp_bios_is_utter_crap = 1;
> -		printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
> -		__asm__ volatile(
> -			"movl %0, %%esp\n\t"
> -			"jmp *%1\n\t"
> -			: : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
> -		panic("do_trap: can't hit this");
> -	}
> -#endif
> -
> -	fixup = search_exception_tables(regs->ip);
> -	if (fixup) {
> -		regs->ip = fixup->fixup;
> -		return 1;
> -	}
> -
> -	return 0;
> -}
> diff --git a/arch/x86/mm/extable_64.c b/arch/x86/mm/extable_64.c
> deleted file mode 100644
> index 79ac6e7..0000000
> --- a/arch/x86/mm/extable_64.c
> +++ /dev/null
> @@ -1,34 +0,0 @@
> -/*
> - * linux/arch/x86_64/mm/extable.c
> - */
> -
> -#include <linux/module.h>
> -#include <linux/spinlock.h>
> -#include <linux/init.h>
> -#include <asm/uaccess.h>
> -
> -/* Simple binary search */
> -const struct exception_table_entry *
> -search_extable(const struct exception_table_entry *first,
> -	       const struct exception_table_entry *last,
> -	       unsigned long value)
> -{
> -	/* Work around a B stepping K8 bug */
> -	if ((value >> 32) == 0)
> -		value |= 0xffffffffUL << 32; 
> -
> -        while (first <= last) {
> -		const struct exception_table_entry *mid;
> -		long diff;
> -
> -		mid = (last - first) / 2 + first;
> -		diff = mid->insn - value;
> -                if (diff == 0)
> -                        return mid;
> -                else if (diff < 0)
> -                        first = mid+1;
> -                else
> -                        last = mid-1;
> -        }
> -        return NULL;
> -}

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com, masami.hiramatsu.pt@hitachi.com

Re: [PATCH] x86: unify extable_{32|64}.c

[Ingo Molnar]

* Masami Hiramatsu <mhiramat@redhat.com> wrote:

> Hi Harvey,
> 
> Harvey Harrison wrote:
> > Introduce fixup_exception() on X86_64 and use it in kprobes to
> > eliminate an #ifdef.
> > 
> > Only X86_64 needs search_extable() due to a stepping bug.
> 
> It's a good work!
> If you can work on it, please add a prototype declaration of
> fixup_exception() in asm-x86/uaccess_64.h too.

FYI, i've already added this to x86.git, it was needed for 64-bit to 
build fine.

	Ingo