[PATCH v3 0/2] MIPS: Remove incorrect `cpu_has_fpu' overrides

[PATCH v3 0/2] MIPS: Remove incorrect `cpu_has_fpu' overrides

[Maciej W. Rozycki]

Hi,

 Forcing `cpu_has_fpu' to 1 is unsupported as it breaks the `nofpu' kernel 
parameter and more recently also the CONFIG_MIPS_FP_SUPPORT configuration 
option.  Remove the broken `cpu_has_fpu' overrides then for IP27 and IP30 
systems.

 This v3 of the series adds credit to Stephen for reporting the issue,
which I forgot on previous iterations.

 Please apply.

  Maciej

[PATCH v3 1/2] MIPS: IP27: Remove incorrect `cpu_has_fpu' override

[Maciej W. Rozycki]

Remove unsupported forcing of `cpu_has_fpu' to 1, which makes the `nofpu' 
kernel parameter non-functional, and also causes a link error:

ld: arch/mips/kernel/traps.o: in function `trap_init':
./arch/mips/include/asm/msa.h:(.init.text+0x348): undefined reference to `handle_fpe'
ld: ./arch/mips/include/asm/msa.h:(.init.text+0x354): undefined reference to `handle_fpe'
ld: ./arch/mips/include/asm/msa.h:(.init.text+0x360): undefined reference to `handle_fpe'

where the CONFIG_MIPS_FP_SUPPORT configuration option has been disabled.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Reported-by: Stephen Zhang <starzhangzsd@gmail.com>
Fixes: 0ebb2f4159af ("MIPS: IP27: Update/restructure CPU overrides")
Cc: stable@vger.kernel.org # v4.2+
---
Changes from v2:

- Give credit to Stephen for reporting the issue.

Changes from v1:

- s/chosen/disabled/ in the change description.
---
 arch/mips/include/asm/mach-ip27/cpu-feature-overrides.h |    1 -
 1 file changed, 1 deletion(-)

linux-mips-ip27-cpu-has-fpu.diff
Index: linux-macro/arch/mips/include/asm/mach-ip27/cpu-feature-overrides.h
===================================================================
--- linux-macro.orig/arch/mips/include/asm/mach-ip27/cpu-feature-overrides.h
+++ linux-macro/arch/mips/include/asm/mach-ip27/cpu-feature-overrides.h
@@ -25,7 +25,6 @@
 #define cpu_has_4kex			1
 #define cpu_has_3k_cache		0
 #define cpu_has_4k_cache		1
-#define cpu_has_fpu			1
 #define cpu_has_nofpuex			0
 #define cpu_has_32fpr			1
 #define cpu_has_counter			1

[PATCH v3 2/2] MIPS: IP30: Remove incorrect `cpu_has_fpu' override

[Maciej W. Rozycki]

Remove unsupported forcing of `cpu_has_fpu' to 1, which makes the `nofpu' 
kernel parameter non-functional, and also causes a link error:

ld: arch/mips/kernel/traps.o: in function `trap_init':
./arch/mips/include/asm/msa.h:(.init.text+0x348): undefined reference to `handle_fpe'
ld: ./arch/mips/include/asm/msa.h:(.init.text+0x354): undefined reference to `handle_fpe'
ld: ./arch/mips/include/asm/msa.h:(.init.text+0x360): undefined reference to `handle_fpe'

where the CONFIG_MIPS_FP_SUPPORT configuration option has been disabled.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Reported-by: Stephen Zhang <starzhangzsd@gmail.com>
Fixes: 7505576d1c1a ("MIPS: add support for SGI Octane (IP30)")
Cc: stable@vger.kernel.org # v5.5+
---
Changes from v2:

- Give credit to Stephen for reporting the issue.

Changes from v1:

- s/chosen/disabled/ in the change description.
---
 arch/mips/include/asm/mach-ip30/cpu-feature-overrides.h |    1 -
 1 file changed, 1 deletion(-)

linux-mips-ip30-cpu-has-fpu.diff
Index: linux-macro/arch/mips/include/asm/mach-ip30/cpu-feature-overrides.h
===================================================================
--- linux-macro.orig/arch/mips/include/asm/mach-ip30/cpu-feature-overrides.h
+++ linux-macro/arch/mips/include/asm/mach-ip30/cpu-feature-overrides.h
@@ -28,7 +28,6 @@
 #define cpu_has_4kex			1
 #define cpu_has_3k_cache		0
 #define cpu_has_4k_cache		1
-#define cpu_has_fpu			1
 #define cpu_has_nofpuex			0
 #define cpu_has_32fpr			1
 #define cpu_has_counter			1

Re: [PATCH v3 0/2] MIPS: Remove incorrect `cpu_has_fpu' overrides

[Thomas Bogendoerfer]

On Sun, May 01, 2022 at 11:14:11PM +0100, Maciej W. Rozycki wrote:
> Hi,
> 
>  Forcing `cpu_has_fpu' to 1 is unsupported as it breaks the `nofpu' kernel 
> parameter and more recently also the CONFIG_MIPS_FP_SUPPORT configuration 
> option.  Remove the broken `cpu_has_fpu' overrides then for IP27 and IP30 
> systems.
> 
>  This v3 of the series adds credit to Stephen for reporting the issue,
> which I forgot on previous iterations.
> 
>  Please apply.

series applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]