From: Palmer Dabbelt palmer@rivosinc.com
[ Upstream commit ad380f6a0a5e82e794b45bb2eaec24ed51a56846 ]
I recently ended up with a warning on some compilers along the lines of
CC kernel/resource.o In file included from include/linux/ioport.h:16, from kernel/resource.c:15: kernel/resource.c: In function 'gfr_start': include/linux/minmax.h:49:37: error: conversion from 'long long unsigned int' to 'resource_size_t' {aka 'unsigned int'} changes value from '17179869183' to '4294967295' [-Werror=overflow] 49 | ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); }) | ^ include/linux/minmax.h:52:9: note: in expansion of macro '__cmp_once_unique' 52 | __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_)) | ^~~~~~~~~~~~~~~~~ include/linux/minmax.h:161:27: note: in expansion of macro '__cmp_once' 161 | #define min_t(type, x, y) __cmp_once(min, type, x, y) | ^~~~~~~~~~ kernel/resource.c:1829:23: note: in expansion of macro 'min_t' 1829 | end = min_t(resource_size_t, base->end, | ^~~~~ kernel/resource.c: In function 'gfr_continue': include/linux/minmax.h:49:37: error: conversion from 'long long unsigned int' to 'resource_size_t' {aka 'unsigned int'} changes value from '17179869183' to '4294967295' [-Werror=overflow] 49 | ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); }) | ^ include/linux/minmax.h:52:9: note: in expansion of macro '__cmp_once_unique' 52 | __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_)) | ^~~~~~~~~~~~~~~~~ include/linux/minmax.h:161:27: note: in expansion of macro '__cmp_once' 161 | #define min_t(type, x, y) __cmp_once(min, type, x, y) | ^~~~~~~~~~ kernel/resource.c:1847:24: note: in expansion of macro 'min_t' 1847 | addr <= min_t(resource_size_t, base->end, | ^~~~~ cc1: all warnings being treated as errors
which looks like a real problem: our phys_addr_t is only 32 bits now, so having 34-bit masks is just going to result in overflows.
Reviewed-by: Charlie Jenkins charlie@rivosinc.com Reviewed-by: Alexandre Ghiti alexghiti@rivosinc.com Link: https://lore.kernel.org/r/20240731162159.9235-2-palmer@rivosinc.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/include/asm/sparsemem.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/include/asm/sparsemem.h b/arch/riscv/include/asm/sparsemem.h index 63acaecc33747..2f901a410586d 100644 --- a/arch/riscv/include/asm/sparsemem.h +++ b/arch/riscv/include/asm/sparsemem.h @@ -7,7 +7,7 @@ #ifdef CONFIG_64BIT #define MAX_PHYSMEM_BITS 56 #else -#define MAX_PHYSMEM_BITS 34 +#define MAX_PHYSMEM_BITS 32 #endif /* CONFIG_64BIT */ #define SECTION_SIZE_BITS 27 #endif /* CONFIG_SPARSEMEM */