[PATCH 0/2] x86: fix longjmp() implementation

[PATCH 0/2] x86: fix longjmp() implementation

[Heinrich Schuchardt]

longjmp() must be defined as

    void longjmp(jmp_buf env, int val)

Add the missing jmp_buf type and fix the definition.
This fixes building the longjmp unit test on qemu-x86_defconfig.

If longjmp(jmp_buf env, int val) is invoked with val == 0, the setjmp()
macro must return 1.

We could have easily discovered this problem and others if unit tests
(CONFIG_UNIT_TEST) were enabled for qemu-x86_defconfig. We should try
to get there in the 2023.01 cycle.

Heinrich Schuchardt (2):
  x86: fix longjmp() implementation
  x86: provide typedef jmp_buf

 arch/x86/cpu/i386/setjmp.S    | 5 +++++
 arch/x86/include/asm/setjmp.h | 6 ++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

-- 
2.37.2

[PATCH 1/2] x86: fix longjmp() implementation

[Heinrich Schuchardt]

If longjmp(jmp_buf env, int val) is called with val = 0, the setjmp()
macro must return 1.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 arch/x86/cpu/i386/setjmp.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/cpu/i386/setjmp.S b/arch/x86/cpu/i386/setjmp.S
index 40b10dc8df..eceeafa7c8 100644
--- a/arch/x86/cpu/i386/setjmp.S
+++ b/arch/x86/cpu/i386/setjmp.S
@@ -49,12 +49,17 @@ longjmp:
 	xchgl %eax, %edx
 #else
 	movl 4(%esp), %edx	/* jmp_ptr address */
+	movl 8(%esp), %eax	/* Return value */
 #endif
 	movl (%edx), %ebx
 	movl 4(%edx), %esp
 	movl 8(%edx), %ebp
 	movl 12(%edx), %esi
 	movl 16(%edx), %edi
+	test %eax, %eax
+	jnz nz
+	inc %eax
+nz:
 	jmp *20(%edx)
 
 	.size longjmp, .-longjmp
-- 
2.37.2

[PATCH 2/2] x86: provide typedef jmp_buf

[Heinrich Schuchardt]

The jmp_buf type is required by the C99 specification.
Defining it for x86 fixes building the longjmp unit test.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 arch/x86/include/asm/setjmp.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/setjmp.h b/arch/x86/include/asm/setjmp.h
index 49c36c1cc8..788d59e231 100644
--- a/arch/x86/include/asm/setjmp.h
+++ b/arch/x86/include/asm/setjmp.h
@@ -34,7 +34,9 @@ struct jmp_buf_data {
 
 #endif
 
-int setjmp(struct jmp_buf_data *jmp_buf);
-void longjmp(struct jmp_buf_data *jmp_buf, int val);
+typedef struct jmp_buf_data jmp_buf[1];
+
+int setjmp(jmp_buf env);
+void longjmp(jmp_buf env, int val);
 
 #endif
-- 
2.37.2

Re: [PATCH 1/2] x86: fix longjmp() implementation

[Simon Glass]

On Sat, 1 Oct 2022 at 07:05, Heinrich Schuchardt
<heinrich.schuchardt@canonical.com> wrote:
>
> If longjmp(jmp_buf env, int val) is called with val = 0, the setjmp()
> macro must return 1.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  arch/x86/cpu/i386/setjmp.S | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/x86/cpu/i386/setjmp.S b/arch/x86/cpu/i386/setjmp.S
> index 40b10dc8df..eceeafa7c8 100644
> --- a/arch/x86/cpu/i386/setjmp.S
> +++ b/arch/x86/cpu/i386/setjmp.S
> @@ -49,12 +49,17 @@ longjmp:
>         xchgl %eax, %edx
>  #else
>         movl 4(%esp), %edx      /* jmp_ptr address */
> +       movl 8(%esp), %eax      /* Return value */
>  #endif
>         movl (%edx), %ebx
>         movl 4(%edx), %esp
>         movl 8(%edx), %ebp
>         movl 12(%edx), %esi
>         movl 16(%edx), %edi
> +       test %eax, %eax
> +       jnz nz
> +       inc %eax
> +nz:
>         jmp *20(%edx)
>
>         .size longjmp, .-longjmp
> --
> 2.37.2
>

Reviewed-by: Simon Glass <sjg@chromium.org>

Re: [PATCH 2/2] x86: provide typedef jmp_buf

[Simon Glass]

Hi Heinrich,

On Sat, 1 Oct 2022 at 07:05, Heinrich Schuchardt
<heinrich.schuchardt@canonical.com> wrote:
>
> The jmp_buf type is required by the C99 specification.
> Defining it for x86 fixes building the longjmp unit test.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  arch/x86/include/asm/setjmp.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Reviewed-by: Simon Glass <sjg@chromium.org>

>
> diff --git a/arch/x86/include/asm/setjmp.h b/arch/x86/include/asm/setjmp.h
> index 49c36c1cc8..788d59e231 100644
> --- a/arch/x86/include/asm/setjmp.h
> +++ b/arch/x86/include/asm/setjmp.h
> @@ -34,7 +34,9 @@ struct jmp_buf_data {
>
>  #endif
>
> -int setjmp(struct jmp_buf_data *jmp_buf);
> -void longjmp(struct jmp_buf_data *jmp_buf, int val);
> +typedef struct jmp_buf_data jmp_buf[1];
> +
> +int setjmp(jmp_buf env);
> +void longjmp(jmp_buf env, int val);
>
>  #endif
> --
> 2.37.2
>

This is an odd test. Where is the failure?

Regards,
Simon

Re: [PATCH 2/2] x86: provide typedef jmp_buf

[Heinrich Schuchardt]

On 10/3/22 03:10, Simon Glass wrote:
> Hi Heinrich,
> 
> On Sat, 1 Oct 2022 at 07:05, Heinrich Schuchardt
> <heinrich.schuchardt@canonical.com> wrote:
>>
>> The jmp_buf type is required by the C99 specification.
>> Defining it for x86 fixes building the longjmp unit test.
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>> ---
>>   arch/x86/include/asm/setjmp.h | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> Reviewed-by: Simon Glass <sjg@chromium.org>
> 
>>
>> diff --git a/arch/x86/include/asm/setjmp.h b/arch/x86/include/asm/setjmp.h
>> index 49c36c1cc8..788d59e231 100644
>> --- a/arch/x86/include/asm/setjmp.h
>> +++ b/arch/x86/include/asm/setjmp.h
>> @@ -34,7 +34,9 @@ struct jmp_buf_data {
>>
>>   #endif
>>
>> -int setjmp(struct jmp_buf_data *jmp_buf);
>> -void longjmp(struct jmp_buf_data *jmp_buf, int val);
>> +typedef struct jmp_buf_data jmp_buf[1];
>> +
>> +int setjmp(jmp_buf env);
>> +void longjmp(jmp_buf env, int val);
>>
>>   #endif
>> --
>> 2.37.2
>>
> 
> This is an odd test. Where is the failure?

qemu-x86_defconfig with CONFIG_UNIT_TEST=y does not build without this 
patch:

test/lib/longjmp.c:15:9: error: unknown type name ‘jmp_buf’
    15 |         jmp_buf env;

Best regards

Heinrich

Re: [PATCH 2/2] x86: provide typedef jmp_buf

[Simon Glass]

On 10/3/22 03:10, Simon Glass wrote:
> Hi Heinrich,
>
> On Sat, 1 Oct 2022 at 07:05, Heinrich Schuchardt
> <heinrich.schuchardt@canonical.com> wrote:
>>
>> The jmp_buf type is required by the C99 specification.
>> Defining it for x86 fixes building the longjmp unit test.
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>> ---
>>   arch/x86/include/asm/setjmp.h | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> Reviewed-by: Simon Glass <sjg@chromium.org>
>
>>
Applied to u-boot-dm, thanks!

Re: [PATCH 1/2] x86: fix longjmp() implementation

[Simon Glass]

On Sat, 1 Oct 2022 at 07:05, Heinrich Schuchardt
<heinrich.schuchardt@canonical.com> wrote:
>
> If longjmp(jmp_buf env, int val) is called with val = 0, the setjmp()
> macro must return 1.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  arch/x86/cpu/i386/setjmp.S | 5 +++++
>  1 file changed, 5 insertions(+)
>
Applied to u-boot-dm, thanks!