From 4f94b2c7462d9720b2afa7e8e8d4c19446bb31ce Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 12 Jan 2018 13:45:33 +0100 Subject: powerpc/8xx: Use L1 entry APG to handle _PAGE_ACCESSED for CONFIG_SWAP When CONFIG_SWAP is set, the TLB miss handlers have to also take into account _PAGE_ACCESSED flag. At the moment it is done by anding _PAGE_ACCESSED into _PAGE_PRESENT using 3 instructions. This patch uses APG for handling _PAGE_ACCESSED, allowing to just copy _PAGE_ACCESSED bit into APG field, hence reducing the action to a single instruction. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/mmu-8xx.h | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) (limited to 'arch/powerpc/include/asm') diff --git a/arch/powerpc/include/asm/mmu-8xx.h b/arch/powerpc/include/asm/mmu-8xx.h index a568ff5c5fb8..2f806e329648 100644 --- a/arch/powerpc/include/asm/mmu-8xx.h +++ b/arch/powerpc/include/asm/mmu-8xx.h @@ -34,12 +34,20 @@ * respectively NA for All or X for Supervisor and no access for User. * Then we use the APG to say whether accesses are according to Page rules or * "all Supervisor" rules (Access to all) - * Therefore, we define 2 APG groups. lsb is _PMD_USER - * 0 => No user => 01 (all accesses performed according to page definition) - * 1 => User => 00 (all accesses performed as supervisor iaw page definition) + * We also use the 2nd APG bit for _PAGE_ACCESSED when having SWAP: + * When that bit is not set access is done iaw "all user" + * which means no access iaw page rules. + * Therefore, we define 4 APG groups. lsb is _PMD_USER, 2nd is _PAGE_ACCESSED + * 0x => No access => 11 (all accesses performed as user iaw page definition) + * 10 => No user => 01 (all accesses performed according to page definition) + * 11 => User => 00 (all accesses performed as supervisor iaw page definition) * We define all 16 groups so that all other bits of APG can take any value */ +#ifdef CONFIG_SWAP +#define MI_APG_INIT 0xf4f4f4f4 +#else #define MI_APG_INIT 0x44444444 +#endif /* The effective page number register. When read, contains the information * about the last instruction TLB miss. When MI_RPN is written, bits in @@ -107,12 +115,20 @@ * Supervisor and no access for user and NA for ALL. * Then we use the APG to say whether accesses are according to Page rules or * "all Supervisor" rules (Access to all) - * Therefore, we define 2 APG groups. lsb is _PMD_USER - * 0 => No user => 01 (all accesses performed according to page definition) - * 1 => User => 00 (all accesses performed as supervisor iaw page definition) + * We also use the 2nd APG bit for _PAGE_ACCESSED when having SWAP: + * When that bit is not set access is done iaw "all user" + * which means no access iaw page rules. + * Therefore, we define 4 APG groups. lsb is _PMD_USER, 2nd is _PAGE_ACCESSED + * 0x => No access => 11 (all accesses performed as user iaw page definition) + * 10 => No user => 01 (all accesses performed according to page definition) + * 11 => User => 00 (all accesses performed as supervisor iaw page definition) * We define all 16 groups so that all other bits of APG can take any value */ +#ifdef CONFIG_SWAP +#define MD_APG_INIT 0xf4f4f4f4 +#else #define MD_APG_INIT 0x44444444 +#endif /* The effective page number register. When read, contains the information * about the last instruction TLB miss. When MD_RPN is written, bits in @@ -164,6 +180,12 @@ */ #define SPRN_M_TW 799 +/* APGs */ +#define M_APG0 0x00000000 +#define M_APG1 0x00000020 +#define M_APG2 0x00000040 +#define M_APG3 0x00000060 + #ifndef __ASSEMBLY__ typedef struct { unsigned int id; -- cgit