| Message ID | 20180417075624.962AB6C038@po15720vm.idsi0.si.c-s.fr (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | powerpc/misc: get rid of add_reloc_offset() | expand |
On Tue, Apr 17, 2018 at 09:56:24AM +0200, Christophe Leroy wrote: > add_reloc_offset() is almost redundant with reloc_offset() > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > --- > arch/powerpc/include/asm/setup.h | 3 +-- > arch/powerpc/kernel/misc.S | 16 ---------------- > arch/powerpc/kernel/prom_init_check.sh | 2 +- > 3 files changed, 2 insertions(+), 19 deletions(-) > > diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h > index 27fa52ed6d00..115e0896ffa7 100644 > --- a/arch/powerpc/include/asm/setup.h > +++ b/arch/powerpc/include/asm/setup.h > @@ -17,10 +17,9 @@ extern void note_scsi_host(struct device_node *, void *); > > /* Used in very early kernel initialization. */ > extern unsigned long reloc_offset(void); > -extern unsigned long add_reloc_offset(unsigned long); > extern void reloc_got2(unsigned long); > > -#define PTRRELOC(x) ((typeof(x)) add_reloc_offset((unsigned long)(x))) > +#define PTRRELOC(x) ((typeof(x)) ((unsigned long)(x) + reloc_offset())) NAK. This is how it used to be, and we changed it in order to prevent gcc from making incorrect assumptions. If you use the form with the explicit addition, and x is the address of an array, gcc will assume that the result is within the bounds of the array (apparently the C standard says it can do that) and potentially generate incorrect code. I recall that we had an actual case where gcc was generating incorrect code, though I don't recall the details, as this was some time before 2002. Paul.
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h index 27fa52ed6d00..115e0896ffa7 100644 --- a/arch/powerpc/include/asm/setup.h +++ b/arch/powerpc/include/asm/setup.h @@ -17,10 +17,9 @@ extern void note_scsi_host(struct device_node *, void *); /* Used in very early kernel initialization. */ extern unsigned long reloc_offset(void); -extern unsigned long add_reloc_offset(unsigned long); extern void reloc_got2(unsigned long); -#define PTRRELOC(x) ((typeof(x)) add_reloc_offset((unsigned long)(x))) +#define PTRRELOC(x) ((typeof(x)) ((unsigned long)(x) + reloc_offset())) void check_for_initrd(void); void mem_topology_setup(void); diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S index 384357cb8bc0..2711b10ebdb3 100644 --- a/arch/powerpc/kernel/misc.S +++ b/arch/powerpc/kernel/misc.S @@ -39,22 +39,6 @@ _GLOBAL(reloc_offset) .align 3 2: PPC_LONG 1b -/* - * add_reloc_offset(x) returns x + reloc_offset(). - */ -_GLOBAL(add_reloc_offset) - mflr r0 - bl 1f -1: mflr r5 - PPC_LL r4,(2f-1b)(r5) - subf r5,r4,r5 - add r3,r3,r5 - mtlr r0 - blr - - .align 3 -2: PPC_LONG 1b - _GLOBAL(setjmp) mflr r0 PPC_STL r0,0(r3) diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh index acb6b9226352..ee9f63186b72 100644 --- a/arch/powerpc/kernel/prom_init_check.sh +++ b/arch/powerpc/kernel/prom_init_check.sh @@ -16,7 +16,7 @@ # If you really need to reference something from prom_init.o add # it to the list below: -WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush +WHITELIST="__bss_start __bss_stop copy_and_flush _end enter_prom memcpy memset reloc_offset __secondary_hold __secondary_hold_acknowledge __secondary_hold_spinloop __start strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224
add_reloc_offset() is almost redundant with reloc_offset() Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/include/asm/setup.h | 3 +-- arch/powerpc/kernel/misc.S | 16 ---------------- arch/powerpc/kernel/prom_init_check.sh | 2 +- 3 files changed, 2 insertions(+), 19 deletions(-)