From c5b367835cfc7a8ef53b9670a409ffcc95194344 Mon Sep 17 00:00:00 2001 From: "Steven J. Hill" Date: Thu, 26 Feb 2015 18:16:38 -0600 Subject: MIPS: Add support for XPA. Add support for extended physical addressing (XPA) so that 32-bit platforms can access equal to or greater than 40 bits of physical addresses. NOTE: 1) XPA and EVA are not the same and cannot be used simultaneously. 2) If you configure your kernel for XPA, the PTEs and all address sizes become 64-bit. 3) Your platform MUST have working HIGHMEM support. Signed-off-by: Steven J. Hill Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9355/ Signed-off-by: Ralf Baechle --- arch/mips/mm/tlbex.c | 90 ++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 77 insertions(+), 13 deletions(-) (limited to 'arch/mips/mm/tlbex.c') diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index 20d985901e44..7709920e0cef 100644 --- a/arch/mips/mm/tlbex.c +++ b/arch/mips/mm/tlbex.c @@ -35,6 +35,17 @@ #include #include +static int __cpuinitdata mips_xpa_disabled; + +static int __init xpa_disable(char *s) +{ + mips_xpa_disabled = 1; + + return 1; +} + +__setup("noxpa", xpa_disable); + /* * TLB load/store/modify handlers. * @@ -1027,12 +1038,27 @@ static void build_update_entries(u32 **p, unsigned int tmp, unsigned int ptep) } else { int pte_off_even = sizeof(pte_t) / 2; int pte_off_odd = pte_off_even + sizeof(pte_t); +#ifdef CONFIG_XPA + const int scratch = 1; /* Our extra working register */ - /* The pte entries are pre-shifted */ - uasm_i_lw(p, tmp, pte_off_even, ptep); /* get even pte */ - UASM_i_MTC0(p, tmp, C0_ENTRYLO0); /* load it */ - uasm_i_lw(p, ptep, pte_off_odd, ptep); /* get odd pte */ - UASM_i_MTC0(p, ptep, C0_ENTRYLO1); /* load it */ + uasm_i_addu(p, scratch, 0, ptep); +#endif + uasm_i_lw(p, tmp, pte_off_even, ptep); /* even pte */ + uasm_i_lw(p, ptep, pte_off_odd, ptep); /* odd pte */ + UASM_i_ROTR(p, tmp, tmp, ilog2(_PAGE_GLOBAL)); + UASM_i_ROTR(p, ptep, ptep, ilog2(_PAGE_GLOBAL)); + UASM_i_MTC0(p, tmp, C0_ENTRYLO0); + UASM_i_MTC0(p, ptep, C0_ENTRYLO1); +#ifdef CONFIG_XPA + uasm_i_lw(p, tmp, 0, scratch); + uasm_i_lw(p, ptep, sizeof(pte_t), scratch); + uasm_i_lui(p, scratch, 0xff); + uasm_i_ori(p, scratch, scratch, 0xffff); + uasm_i_and(p, tmp, scratch, tmp); + uasm_i_and(p, ptep, scratch, ptep); + uasm_i_mthc0(p, tmp, C0_ENTRYLO0); + uasm_i_mthc0(p, ptep, C0_ENTRYLO1); +#endif } #else UASM_i_LW(p, tmp, 0, ptep); /* get even pte */ @@ -1533,8 +1559,14 @@ iPTE_SW(u32 **p, struct uasm_reloc **r, unsigned int pte, unsigned int ptr, { #ifdef CONFIG_PHYS_ADDR_T_64BIT unsigned int hwmode = mode & (_PAGE_VALID | _PAGE_DIRTY); -#endif + if (!cpu_has_64bits) { + const int scratch = 1; /* Our extra working register */ + + uasm_i_lui(p, scratch, (mode >> 16)); + uasm_i_or(p, pte, pte, scratch); + } else +#endif uasm_i_ori(p, pte, pte, mode); #ifdef CONFIG_SMP # ifdef CONFIG_PHYS_ADDR_T_64BIT @@ -1598,15 +1630,17 @@ build_pte_present(u32 **p, struct uasm_reloc **r, uasm_il_bbit0(p, r, pte, ilog2(_PAGE_PRESENT), lid); uasm_i_nop(p); } else { - uasm_i_andi(p, t, pte, _PAGE_PRESENT); + uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT); + uasm_i_andi(p, t, t, 1); uasm_il_beqz(p, r, t, lid); if (pte == t) /* You lose the SMP race :-(*/ iPTE_LW(p, pte, ptr); } } else { - uasm_i_andi(p, t, pte, _PAGE_PRESENT | _PAGE_READ); - uasm_i_xori(p, t, t, _PAGE_PRESENT | _PAGE_READ); + uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT); + uasm_i_andi(p, t, t, 3); + uasm_i_xori(p, t, t, 3); uasm_il_bnez(p, r, t, lid); if (pte == t) /* You lose the SMP race :-(*/ @@ -1635,8 +1669,9 @@ build_pte_writable(u32 **p, struct uasm_reloc **r, { int t = scratch >= 0 ? scratch : pte; - uasm_i_andi(p, t, pte, _PAGE_PRESENT | _PAGE_WRITE); - uasm_i_xori(p, t, t, _PAGE_PRESENT | _PAGE_WRITE); + uasm_i_srl(p, t, pte, _PAGE_PRESENT_SHIFT); + uasm_i_andi(p, t, t, 5); + uasm_i_xori(p, t, t, 5); uasm_il_bnez(p, r, t, lid); if (pte == t) /* You lose the SMP race :-(*/ @@ -1672,7 +1707,8 @@ build_pte_modifiable(u32 **p, struct uasm_reloc **r, uasm_i_nop(p); } else { int t = scratch >= 0 ? scratch : pte; - uasm_i_andi(p, t, pte, _PAGE_WRITE); + uasm_i_srl(p, t, pte, _PAGE_WRITE_SHIFT); + uasm_i_andi(p, t, t, 1); uasm_il_beqz(p, r, t, lid); if (pte == t) /* You lose the SMP race :-(*/ @@ -2285,6 +2321,11 @@ static void config_htw_params(void) pwsize = ilog2(PTRS_PER_PGD) << MIPS_PWSIZE_GDW_SHIFT; pwsize |= ilog2(PTRS_PER_PTE) << MIPS_PWSIZE_PTW_SHIFT; + + /* If XPA has been enabled, PTEs are 64-bit in size. */ + if (read_c0_pagegrain() & PG_ELPA) + pwsize |= 1; + write_c0_pwsize(pwsize); /* Make sure everything is set before we enable the HTW */ @@ -2298,6 +2339,28 @@ static void config_htw_params(void) print_htw_config(); } +static void config_xpa_params(void) +{ +#ifdef CONFIG_XPA + unsigned int pagegrain; + + if (mips_xpa_disabled) { + pr_info("Extended Physical Addressing (XPA) disabled\n"); + return; + } + + pagegrain = read_c0_pagegrain(); + write_c0_pagegrain(pagegrain | PG_ELPA); + back_to_back_c0_hazard(); + pagegrain = read_c0_pagegrain(); + + if (pagegrain & PG_ELPA) + pr_info("Extended Physical Addressing (XPA) enabled\n"); + else + panic("Extended Physical Addressing (XPA) disabled"); +#endif +} + void build_tlb_refill_handler(void) { /* @@ -2362,8 +2425,9 @@ void build_tlb_refill_handler(void) } if (cpu_has_local_ebase) build_r4000_tlb_refill_handler(); + if (cpu_has_xpa) + config_xpa_params(); if (cpu_has_htw) config_htw_params(); - } } -- cgit v1.2.3