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alpha: Define pgprot_modify to silence tautological comparison warnings

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Alpha's pgprot_noncached, pgprot_writecombine, and pgprot_device are
all identity macros, so the generic pgprot_modify() produces
tautological self-comparisons that GCC warns about:

  include/linux/pgtable.h:1701:25: warning: self-comparison always
  evaluates to true [-Wtautological-compare]

Since all caching attributes are no-ops on Alpha, define
pgprot_modify() to simply return newprot.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Magnus Lindholm <linmag7@gmail.com>
Link: https://lore.kernel.org/r/20260403150128.488513-1-mattst88@gmail.com
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
This commit is contained in:
Matt Turner
2026-04-03 11:01:28 -04:00
committed by Magnus Lindholm
parent 55b22075f7
commit bd39fc8134
1 changed files with 11 additions and 0 deletions
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11
arch/alpha/include/asm/pgtable.h
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@@ -126,6 +126,17 @@ struct vm_area_struct;
*/
#define pgprot_noncached(prot) (prot)
/*
* All caching attribute macros are identity on Alpha, so the generic
* pgprot_modify() degenerates to tautological self-comparisons.
* Override it to just return newprot directly.
*/
#define pgprot_modify pgprot_modify
static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
{
return newprot;
}
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..