[PATCH] mips: fix Section mismatch in reference

[PATCH] mips: fix Section mismatch in reference

[Anders Roxell]

commit ad4fddef5f2345aa9214e979febe2f47639c10d9 upstream.

When building mips tinyconfig with clang the following error show up:

WARNING: modpost: vmlinux.o(.text+0x1940c): Section mismatch in reference from the function r4k_cache_init() to the function .init.text:loongson3_sc_init()
The function r4k_cache_init() references
the function __init loongson3_sc_init().
This is often because r4k_cache_init lacks a __init
annotation or the annotation of loongson3_sc_init is wrong.

Remove marked __init from function loongson3_sc_init(),
mips_sc_probe_cm3(), and mips_sc_probe().

Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
---
 arch/mips/mm/c-r4k.c   | 2 +-
 arch/mips/mm/sc-mips.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 9cede7ce37e6..c9644c38ec28 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1609,7 +1609,7 @@ static void __init loongson2_sc_init(void)
 	c->options |= MIPS_CPU_INCLUSIVE_CACHES;
 }
 
-static void __init loongson3_sc_init(void)
+static void loongson3_sc_init(void)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	unsigned int config2, lsize;
diff --git a/arch/mips/mm/sc-mips.c b/arch/mips/mm/sc-mips.c
index dd0a5becaabd..06ec304ad4d1 100644
--- a/arch/mips/mm/sc-mips.c
+++ b/arch/mips/mm/sc-mips.c
@@ -146,7 +146,7 @@ static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
 	return 1;
 }
 
-static int __init mips_sc_probe_cm3(void)
+static int mips_sc_probe_cm3(void)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	unsigned long cfg = read_gcr_l2_config();
@@ -180,7 +180,7 @@ static int __init mips_sc_probe_cm3(void)
 	return 0;
 }
 
-static inline int __init mips_sc_probe(void)
+static inline int mips_sc_probe(void)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	unsigned int config1, config2;
-- 
2.29.2

[PATCH] mips: lib: uncached: fix non-standard usage of variable 'sp'

[Anders Roxell]

commit 5b058973d3205578aa6c9a71392e072a11ca44ef upstream.

When building mips tinyconfig with clang the following warning show up:

arch/mips/lib/uncached.c:45:6: warning: variable 'sp' is uninitialized when used here [-Wuninitialized]
        if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
            ^~
arch/mips/lib/uncached.c:40:18: note: initialize the variable 'sp' to silence this warning
        register long sp __asm__("$sp");
                        ^
                         = 0
1 warning generated.

Rework to make an explicit inline move, instead of the non-standard use
of specifying registers for local variables. This is what's written
from the gcc-10 manual [1] about specifying registers for local
variables:

"6.47.5.2 Specifying Registers for Local Variables
.................................................
[...]

"The only supported use for this feature is to specify registers for
input and output operands when calling Extended 'asm' (*note Extended
Asm::).  [...]".

Cc: <stable@vger.kernel.org> # v5.4+
[1] https://docs.w3cub.com/gcc~10/local-register-variables
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
---
 arch/mips/lib/uncached.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
index 09d5deea747f..f80a67c092b6 100644
--- a/arch/mips/lib/uncached.c
+++ b/arch/mips/lib/uncached.c
@@ -37,10 +37,12 @@
  */
 unsigned long run_uncached(void *func)
 {
-	register long sp __asm__("$sp");
 	register long ret __asm__("$2");
 	long lfunc = (long)func, ufunc;
 	long usp;
+	long sp;
+
+	__asm__("move %0, $sp" : "=r" (sp));
 
 	if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
 		usp = CKSEG1ADDR(sp);
-- 
2.29.2

[PATCH] mips: fix Section mismatch in reference

[Anders Roxell]

When building mips tinyconfig with clang the following error show up:

WARNING: modpost: vmlinux.o(.text+0x1940c): Section mismatch in reference from the function r4k_cache_init() to the function .init.text:loongson3_sc_init()
The function r4k_cache_init() references
the function __init loongson3_sc_init().
This is often because r4k_cache_init lacks a __init
annotation or the annotation of loongson3_sc_init is wrong.

Remove marked __init from function loongson3_sc_init(),
mips_sc_probe_cm3(), and mips_sc_probe().

Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
---
 arch/mips/mm/c-r4k.c   | 2 +-
 arch/mips/mm/sc-mips.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 99521764c75b..4f976d687ab0 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1609,7 +1609,7 @@ static void __init loongson2_sc_init(void)
 	c->options |= MIPS_CPU_INCLUSIVE_CACHES;
 }
 
-static void __init loongson3_sc_init(void)
+static void loongson3_sc_init(void)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	unsigned int config2, lsize;
diff --git a/arch/mips/mm/sc-mips.c b/arch/mips/mm/sc-mips.c
index dd0a5becaabd..06ec304ad4d1 100644
--- a/arch/mips/mm/sc-mips.c
+++ b/arch/mips/mm/sc-mips.c
@@ -146,7 +146,7 @@ static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
 	return 1;
 }
 
-static int __init mips_sc_probe_cm3(void)
+static int mips_sc_probe_cm3(void)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	unsigned long cfg = read_gcr_l2_config();
@@ -180,7 +180,7 @@ static int __init mips_sc_probe_cm3(void)
 	return 0;
 }
 
-static inline int __init mips_sc_probe(void)
+static inline int mips_sc_probe(void)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	unsigned int config1, config2;
-- 
2.29.2

Re: [PATCH] mips: fix Section mismatch in reference

[Nick Desaulniers]

On Fri, Nov 27, 2020 at 12:39 AM Anders Roxell <anders.roxell@linaro.org> wrote:
>
> When building mips tinyconfig with clang the following error show up:
>
> WARNING: modpost: vmlinux.o(.text+0x1940c): Section mismatch in reference from the function r4k_cache_init() to the function .init.text:loongson3_sc_init()
> The function r4k_cache_init() references
> the function __init loongson3_sc_init().

Looks like loongson2_sc_init() might also have the same problem? (Both
loongson2_sc_init  and loongson3_sc_init are called from non-__init
setup_scache).  Trying to pinpoint a Fixes tag is tricky, it looks
like setup_scache used to be marked __init, then __cpuinit?

> This is often because r4k_cache_init lacks a __init
> annotation or the annotation of loongson3_sc_init is wrong.
>
> Remove marked __init from function loongson3_sc_init(),
> mips_sc_probe_cm3(), and mips_sc_probe().

mips_sc_probe_cm3() is only called from mips_sc_probe() which is
marked as __init.  mips_sc_probe is only called from mips_sc_init,
which is not marked __init.

So the patch is fine (and thanks for sending it):

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

though it looks like it might be worthwhile for the MIPS maintainer or
Loongson folks to see if they can lower the kernel image size in
memory post init by possibly re-adding __init to
setup_scache()/r4k_cache_init()/cpu_cache_init() and friends.

>
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> ---
>  arch/mips/mm/c-r4k.c   | 2 +-
>  arch/mips/mm/sc-mips.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
> index 99521764c75b..4f976d687ab0 100644
> --- a/arch/mips/mm/c-r4k.c
> +++ b/arch/mips/mm/c-r4k.c
> @@ -1609,7 +1609,7 @@ static void __init loongson2_sc_init(void)
>         c->options |= MIPS_CPU_INCLUSIVE_CACHES;
>  }
>
> -static void __init loongson3_sc_init(void)
> +static void loongson3_sc_init(void)
>  {
>         struct cpuinfo_mips *c = &current_cpu_data;
>         unsigned int config2, lsize;
> diff --git a/arch/mips/mm/sc-mips.c b/arch/mips/mm/sc-mips.c
> index dd0a5becaabd..06ec304ad4d1 100644
> --- a/arch/mips/mm/sc-mips.c
> +++ b/arch/mips/mm/sc-mips.c
> @@ -146,7 +146,7 @@ static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
>         return 1;
>  }
>
> -static int __init mips_sc_probe_cm3(void)
> +static int mips_sc_probe_cm3(void)
>  {
>         struct cpuinfo_mips *c = &current_cpu_data;
>         unsigned long cfg = read_gcr_l2_config();
> @@ -180,7 +180,7 @@ static int __init mips_sc_probe_cm3(void)
>         return 0;
>  }
>
> -static inline int __init mips_sc_probe(void)
> +static inline int mips_sc_probe(void)
>  {
>         struct cpuinfo_mips *c = &current_cpu_data;
>         unsigned int config1, config2;
> --
> 2.29.2
>


-- 
Thanks,
~Nick Desaulniers