| Message ID | 20150120095736.518681A5E86@localhost.localdomain (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Scott Wood |
| Headers | show |
On Tue, 2015-01-20 at 10:57 +0100, Christophe Leroy wrote: > By default, TASK_SIZE is set to 0x80000000 for PPC_8xx, which is most likely > sufficient for most cases. However, kernel configuration allows to set TASK_SIZE > to another value, so the 8xx shall handle it. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > > --- > v2: no change > > arch/powerpc/kernel/head_8xx.S | 25 +++++++++++++++++++------ > 1 file changed, 19 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S > index ead6448..92a6456 100644 > --- a/arch/powerpc/kernel/head_8xx.S > +++ b/arch/powerpc/kernel/head_8xx.S > @@ -48,6 +48,19 @@ > mtspr spr, reg > #endif > > +/* Macro to test if an address is a kernel address */ > +#if CONFIG_TASK_SIZE <= 0x80000000 > +#define IS_KERNEL(tmp, addr) \ > + andis. tmp, addr, 0x8000 /* Address >= 0x80000000 */ > +#define BRANCH_UNLESS_KERNEL(label) beq label > +#else This works if CONFIG_TASK_SIZE == 0x80000000, but what if it's less, and you have a kernel address < 0x80000000? -Scott
Le 21/03/2015 01:47, Scott Wood a écrit : > On Tue, 2015-01-20 at 10:57 +0100, Christophe Leroy wrote: >> By default, TASK_SIZE is set to 0x80000000 for PPC_8xx, which is most likely >> sufficient for most cases. However, kernel configuration allows to set TASK_SIZE >> to another value, so the 8xx shall handle it. >> >> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> >> >> --- >> v2: no change >> >> arch/powerpc/kernel/head_8xx.S | 25 +++++++++++++++++++------ >> 1 file changed, 19 insertions(+), 6 deletions(-) >> >> diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S >> index ead6448..92a6456 100644 >> --- a/arch/powerpc/kernel/head_8xx.S >> +++ b/arch/powerpc/kernel/head_8xx.S >> @@ -48,6 +48,19 @@ >> mtspr spr, reg >> #endif >> >> +/* Macro to test if an address is a kernel address */ >> +#if CONFIG_TASK_SIZE <= 0x80000000 >> +#define IS_KERNEL(tmp, addr) \ >> + andis. tmp, addr, 0x8000 /* Address >= 0x80000000 */ >> +#define BRANCH_UNLESS_KERNEL(label) beq label >> +#else > This works if CONFIG_TASK_SIZE == 0x80000000, but what if it's less, and > you have a kernel address < 0x80000000? > > You are right, I didn't realise that PAGE_OFFSET was also configurable and could be different from 0xC0000000. andis. (which is what is always used in the current kernel) can be used if CONFIG_TASK_SIZE <= 0x80000000 AND PAGE_OFFSET >= 0x80000000. I will resubmit the patch accordingly. Christophe
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index ead6448..92a6456 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -48,6 +48,19 @@ mtspr spr, reg #endif +/* Macro to test if an address is a kernel address */ +#if CONFIG_TASK_SIZE <= 0x80000000 +#define IS_KERNEL(tmp, addr) \ + andis. tmp, addr, 0x8000 /* Address >= 0x80000000 */ +#define BRANCH_UNLESS_KERNEL(label) beq label +#else +#define IS_KERNEL(tmp, addr) \ + rlwinm tmp, addr, 16, 16, 31; \ + cmpli cr0, tmp, PAGE_OFFSET >> 16 +#define BRANCH_UNLESS_KERNEL(label) blt label +#endif + + /* * Value for the bits that have fixed value in RPN entries. * Also used for tagging DAR for DTLBerror. @@ -322,9 +335,9 @@ InstructionTLBMiss: mfspr r11, SPRN_SRR0 /* Get effective address of fault */ DO_8xx_CPU15(r10, r11) mfcr r10 - andis. r11, r11, 0x8000 /* Address >= 0x80000000 */ + IS_KERNEL(r11, r11) mfspr r11, SPRN_M_TW /* Get level 1 table */ - beq 3f + BRANCH_UNLESS_KERNEL(3f) lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha 3: mtcr r10 @@ -379,9 +392,9 @@ DataStoreTLBMiss: * kernel page tables. */ mfspr r11, SPRN_MD_EPN - andis. r11, r11, 0x8000 + IS_KERNEL(r11, r11) mfspr r11, SPRN_M_TW /* Get level 1 table */ - beq 3f + BRANCH_UNLESS_KERNEL(3f) lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha 3: mtcr r10 @@ -516,9 +529,9 @@ FixupDAR:/* Entry point for dcbx workaround. */ mtspr SPRN_SPRG_SCRATCH2, r10 /* fetch instruction from memory. */ mfspr r10, SPRN_SRR0 - andis. r11, r10, 0x8000 /* Address >= 0x80000000 */ + IS_KERNEL(r11, r10) mfspr r11, SPRN_M_TW /* Get level 1 table */ - beq 3f + BRANCH_UNLESS_KERNEL(3f) lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha /* Insert level 1 index */ 3: rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29
By default, TASK_SIZE is set to 0x80000000 for PPC_8xx, which is most likely sufficient for most cases. However, kernel configuration allows to set TASK_SIZE to another value, so the 8xx shall handle it. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- v2: no change arch/powerpc/kernel/head_8xx.S | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-)