| Message ID | a6781075192afe0c909ce7d091de7931183a5d93.1566219503.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/3] powerpc: don't use __WARN() for WARN_ON() | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (c9633332103e55bc73d80d07ead28b95a22a85a3) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 8 lines checked |
On Mon, Aug 19, 2019 at 01:06:28PM +0000, Christophe Leroy wrote: > __WARN() used to just call __WARN_TAINT(TAINT_WARN) > > But a call to printk() has been added in the commit identified below > to print a "---- cut here ----" line. > > This change only applies to warnings using __WARN(), which means > WARN_ON() where the condition is constant at compile time. > For WARN_ON() with a non constant condition, the additional line is > not printed. > > In addition, adding a call to printk() forces GCC to add a stack frame > and save volatile registers. Powerpc has been using traps to implement > warnings in order to avoid that. > > So, call __WARN_TAINT(TAINT_WARN) directly instead of using __WARN() > in order to restore the previous behaviour. > > If one day powerpc wants the decorative "---- cut here ----" line, it > has to be done in the trap handler, not in the WARN_ON() macro. > > Fixes: 6b15f678fb7d ("include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures") > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Ah! Hmpf. Yeah, that wasn't an intended side-effect of this fix. It seems PPC is not alone in this situation of making this code much noisier. It looks like there needs to be a way to indicate to the trap handler that a message was delivered or not. Perhaps we can add another taint flag? -kees > --- > arch/powerpc/include/asm/bug.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h > index fed7e6241349..3928fdaebb71 100644 > --- a/arch/powerpc/include/asm/bug.h > +++ b/arch/powerpc/include/asm/bug.h > @@ -99,7 +99,7 @@ > int __ret_warn_on = !!(x); \ > if (__builtin_constant_p(__ret_warn_on)) { \ > if (__ret_warn_on) \ > - __WARN(); \ > + __WARN_TAINT(TAINT_WARN); \ > } else { \ > __asm__ __volatile__( \ > "1: "PPC_TLNEI" %4,0\n" \ > -- > 2.13.3 >
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index fed7e6241349..3928fdaebb71 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -99,7 +99,7 @@ int __ret_warn_on = !!(x); \ if (__builtin_constant_p(__ret_warn_on)) { \ if (__ret_warn_on) \ - __WARN(); \ + __WARN_TAINT(TAINT_WARN); \ } else { \ __asm__ __volatile__( \ "1: "PPC_TLNEI" %4,0\n" \
__WARN() used to just call __WARN_TAINT(TAINT_WARN) But a call to printk() has been added in the commit identified below to print a "---- cut here ----" line. This change only applies to warnings using __WARN(), which means WARN_ON() where the condition is constant at compile time. For WARN_ON() with a non constant condition, the additional line is not printed. In addition, adding a call to printk() forces GCC to add a stack frame and save volatile registers. Powerpc has been using traps to implement warnings in order to avoid that. So, call __WARN_TAINT(TAINT_WARN) directly instead of using __WARN() in order to restore the previous behaviour. If one day powerpc wants the decorative "---- cut here ----" line, it has to be done in the trap handler, not in the WARN_ON() macro. Fixes: 6b15f678fb7d ("include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures") Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/include/asm/bug.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)