[PATCH 0/2] powerpc64/bpf: Fix PCREL build breaks

[PATCH 0/2] powerpc64/bpf: Fix PCREL build breaks

[Saket Kumar Bhaskar]

This series fixes two build failures that occur when
CONFIG_PPC_KERNEL_PCREL is enabled on powerpc64.

Patch 1 fixes an unused variable warning in bpf_jit_emit_func_call_rel()
by marking the variable as __maybe_unused, since it's only used in the
non-PCREL code path.

Patch 2 fixes a linker error in arch_bpf_timed_may_goto() by using the
CFUNC() macro for external C function calls. The macro properly handles
the @notoc annotation required for PCREL builds, informing the linker
that TOC restoration is not needed.

Both issues were introduced by commit b55b6b9ad76c ("powerpc64/bpf: Add
powerpc64 JIT support for timed may_goto").

Madhavan Srinivasan (1):
  powerpc64/bpf: Fix build break in bpf_jit_emit_func_call_rel()

Saket Kumar Bhaskar (1):
  powerpc64/bpf: Fix build break for arch_bpf_timed_may_goto

 arch/powerpc/net/bpf_jit_comp64.c     | 2 +-
 arch/powerpc/net/bpf_timed_may_goto.S | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
2.54.0

[PATCH 1/2] powerpc64/bpf: Fix build break in bpf_jit_emit_func_call_rel()

[Saket Kumar Bhaskar]

From: Madhavan Srinivasan <maddy@linux.ibm.com>

With CONFIG_PPC_KERNEL_PCREL enabled, build breaks with below error:

  CC      mm/dmapool.o
  CC      fs/readdir.o
arch/powerpc/net/bpf_jit_comp64.c: In function 'bpf_jit_emit_func_call_rel':
arch/powerpc/net/bpf_jit_comp64.c:475:13: error: unused variable 'ret' [-Werror=unused-variable]
  475 |         int ret;
      |             ^~~

commit b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for timed may_goto")
introduced "ret" variable to bpf_jit_emit_func_call_rel() and it is used only in
else block of CONFIG_PPC_KERNEL_PCREL, fix by adding a "__maybe_unused"

Fixes: b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for timed may_goto")
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
---
 arch/powerpc/net/bpf_jit_comp64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index dab106cae22b..63952ef19256 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -472,7 +472,7 @@ int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *
 {
 	unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0;
 	long __maybe_unused reladdr;
-	int ret;
+	int __maybe_unused ret;
 
 	/* bpf to bpf call, func is not known in the initial pass. Emit 5 nops as a placeholder */
 	if (!func) {
-- 
2.54.0

Re: [PATCH 1/2] powerpc64/bpf: Fix build break in bpf_jit_emit_func_call_rel()

[Christophe Leroy (CS GROUP)]

Le 29/07/2026 à 18:03, Saket Kumar Bhaskar a écrit :
> From: Madhavan Srinivasan <maddy@linux.ibm.com>
> 
> With CONFIG_PPC_KERNEL_PCREL enabled, build breaks with below error:
> 
>    CC      mm/dmapool.o
>    CC      fs/readdir.o
> arch/powerpc/net/bpf_jit_comp64.c: In function 'bpf_jit_emit_func_call_rel':
> arch/powerpc/net/bpf_jit_comp64.c:475:13: error: unused variable 'ret' [-Werror=unused-variable]
>    475 |         int ret;
>        |             ^~~
> 
> commit b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for timed may_goto")
> introduced "ret" variable to bpf_jit_emit_func_call_rel() and it is used only in
> else block of CONFIG_PPC_KERNEL_PCREL, fix by adding a "__maybe_unused"

__maybe_unused doesn't fix the problem, it just hides it under the carpet.

ret is used at only one place, move it's declaration their:

#else
	if (core_kernel_text(func_addr)) {
		int ret = bpf_jit_emit_func_call(image, ctx, func_addr, _R12);
		if (ret)
			return ret;
	} else {

> 
> Fixes: b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for timed may_goto")
> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> ---
>   arch/powerpc/net/bpf_jit_comp64.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> index dab106cae22b..63952ef19256 100644
> --- a/arch/powerpc/net/bpf_jit_comp64.c
> +++ b/arch/powerpc/net/bpf_jit_comp64.c
> @@ -472,7 +472,7 @@ int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *
>   {
>   	unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0;
>   	long __maybe_unused reladdr;
> -	int ret;
> +	int __maybe_unused ret;
>   
>   	/* bpf to bpf call, func is not known in the initial pass. Emit 5 nops as a placeholder */
>   	if (!func) {

Re: [PATCH 1/2] powerpc64/bpf: Fix build break in bpf_jit_emit_func_call_rel()

[Madhavan Srinivasan]

On 7/29/26 10:15 PM, Christophe Leroy (CS GROUP) wrote:
>
>
> Le 29/07/2026 à 18:03, Saket Kumar Bhaskar a écrit :
>> From: Madhavan Srinivasan <maddy@linux.ibm.com>
>>
>> With CONFIG_PPC_KERNEL_PCREL enabled, build breaks with below error:
>>
>>    CC      mm/dmapool.o
>>    CC      fs/readdir.o
>> arch/powerpc/net/bpf_jit_comp64.c: In function 
>> 'bpf_jit_emit_func_call_rel':
>> arch/powerpc/net/bpf_jit_comp64.c:475:13: error: unused variable 
>> 'ret' [-Werror=unused-variable]
>>    475 |         int ret;
>>        |             ^~~
>>
>> commit b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for 
>> timed may_goto")
>> introduced "ret" variable to bpf_jit_emit_func_call_rel() and it is 
>> used only in
>> else block of CONFIG_PPC_KERNEL_PCREL, fix by adding a "__maybe_unused"
>
> __maybe_unused doesn't fix the problem, it just hides it under the 
> carpet.
>
My bad, took the precedence from reladdr, may be it is better to change 
that too then

Maddy
> ret is used at only one place, move it's declaration their:
>
> #else
>     if (core_kernel_text(func_addr)) {
>         int ret = bpf_jit_emit_func_call(image, ctx, func_addr, _R12);
>         if (ret)
>             return ret;
>     } else {
>
>>
>> Fixes: b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for 
>> timed may_goto")
>> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
>> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
>> ---
>>   arch/powerpc/net/bpf_jit_comp64.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/net/bpf_jit_comp64.c 
>> b/arch/powerpc/net/bpf_jit_comp64.c
>> index dab106cae22b..63952ef19256 100644
>> --- a/arch/powerpc/net/bpf_jit_comp64.c
>> +++ b/arch/powerpc/net/bpf_jit_comp64.c
>> @@ -472,7 +472,7 @@ int bpf_jit_emit_func_call_rel(u32 *image, u32 
>> *fimage, struct codegen_context *
>>   {
>>       unsigned long func_addr = func ? ppc_function_entry((void 
>> *)func) : 0;
>>       long __maybe_unused reladdr;
>> -    int ret;
>> +    int __maybe_unused ret;
>>         /* bpf to bpf call, func is not known in the initial pass. 
>> Emit 5 nops as a placeholder */
>>       if (!func) {
>

[PATCH 2/2] powerpc64/bpf: Fix build break for arch_bpf_timed_may_goto

[Saket Kumar Bhaskar]

With CONFIG_PPC_KERNEL_PCREL enabled, calling bpf_check_timed_may_goto()
using a bl instruction results in a link-time failure:

arch/powerpc/net/bpf_timed_may_goto.o: in function `arch_bpf_timed_may_goto':
(.text+0x28): call to `bpf_check_timed_may_goto' lacks nop, can't restore toc

Use CFUNC() macro instead of direct 'bl' to properly annotate the call
to bpf_check_timed_may_goto(). On PCREL builds, CFUNC() expands to
'bl name@notoc', informing the linker that TOC restoration is not
needed, avoiding the "lacks nop, can't restore toc" linker error.

Fixes: b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for timed may_goto")
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
---
 arch/powerpc/net/bpf_timed_may_goto.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_timed_may_goto.S b/arch/powerpc/net/bpf_timed_may_goto.S
index 6fd8b1c9f4ac..84ecf6fa7f5d 100644
--- a/arch/powerpc/net/bpf_timed_may_goto.S
+++ b/arch/powerpc/net/bpf_timed_may_goto.S
@@ -36,7 +36,7 @@ SYM_FUNC_START(arch_bpf_timed_may_goto)
 	 * BPF_REG_FP is r31; BPF_REG_AX is r12 (stack offset in bytes).
 	 */
 	add     r3, r31, r12
-	bl      bpf_check_timed_may_goto
+	bl      CFUNC(bpf_check_timed_may_goto)
 
 	/* Put return value back into AX */
 	mr      r12, r3
-- 
2.54.0

Re: [PATCH 2/2] powerpc64/bpf: Fix build break for arch_bpf_timed_may_goto

[Christophe Leroy (CS GROUP)]

Le 29/07/2026 à 18:03, Saket Kumar Bhaskar a écrit :
> With CONFIG_PPC_KERNEL_PCREL enabled, calling bpf_check_timed_may_goto()
> using a bl instruction results in a link-time failure:
> 
> arch/powerpc/net/bpf_timed_may_goto.o: in function `arch_bpf_timed_may_goto':
> (.text+0x28): call to `bpf_check_timed_may_goto' lacks nop, can't restore toc
> 
> Use CFUNC() macro instead of direct 'bl' to properly annotate the call
> to bpf_check_timed_may_goto(). On PCREL builds, CFUNC() expands to
> 'bl name@notoc', informing the linker that TOC restoration is not
> needed, avoiding the "lacks nop, can't restore toc" linker error.
> 
> Fixes: b55b6b9ad76c ("powerpc64/bpf: Add powerpc64 JIT support for timed may_goto")
> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>

Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>

> ---
>   arch/powerpc/net/bpf_timed_may_goto.S | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/net/bpf_timed_may_goto.S b/arch/powerpc/net/bpf_timed_may_goto.S
> index 6fd8b1c9f4ac..84ecf6fa7f5d 100644
> --- a/arch/powerpc/net/bpf_timed_may_goto.S
> +++ b/arch/powerpc/net/bpf_timed_may_goto.S
> @@ -36,7 +36,7 @@ SYM_FUNC_START(arch_bpf_timed_may_goto)
>   	 * BPF_REG_FP is r31; BPF_REG_AX is r12 (stack offset in bytes).
>   	 */
>   	add     r3, r31, r12
> -	bl      bpf_check_timed_may_goto
> +	bl      CFUNC(bpf_check_timed_may_goto)
>   
>   	/* Put return value back into AX */
>   	mr      r12, r3