On Fri, Apr 15, 2016 at 11:36:55AM +0100, Paul Burton wrote:
> There are 2 distinct cases in which a kernel for a MIPS32 CPU
> (CONFIG_CPU_MIPS32=y) may use 64 bit physical addresses
> (CONFIG_PHYS_ADDR_T_64BIT=y):
>
> - 36 bit physical addressing as used by RMI Alchemy & Netlogic XLP/XLR
> CPUs.
>
> - MIPS32r5 eXtended Physical Addressing (XPA).
>
> These 2 cases are distinct in that they require different behaviour from
> the kernel - the EntryLo registers have different formats. Until Linux
> v4.1 we only supported the first case, with code conditional upon the 2
> aforementioned Kconfig variables being set. Commit c5b367835cfc ("MIPS:
> Add support for XPA.") added support for the second case, but did so by
> modifying the code that existed for the first case rather than treating
> the 2 cases as distinct. Since the EntryLo registers have different
> formats this breaks the 36 bit Alchemy/XLP/XLR case. Fix this by
> splitting the 2 cases, with XPA cases now being conditional upon
> CONFIG_XPA and the non-XPA case matching the code as it existed prior to
> commit c5b367835cfc ("MIPS: Add support for XPA.").
>
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
> Reported-by: Manuel Lauss <manuel.lauss@xxxxxxxxx>
> Tested-by: Manuel Lauss <manuel.lauss@xxxxxxxxx>
> Fixes: c5b367835cfc ("MIPS: Add support for XPA.")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.1+
> ---
>
> arch/mips/include/asm/pgtable-32.h | 27 +++++++++++++++++++++++++--
> arch/mips/include/asm/pgtable-bits.h | 29 +++++++++++++++++++++++++----
> arch/mips/include/asm/pgtable.h | 32 ++++++++++++++++++++++++++++++--
> arch/mips/mm/init.c | 4 +++-
> arch/mips/mm/tlbex.c | 35 +++++++++++++++++++++++------------
> 5 files changed, 106 insertions(+), 21 deletions(-)
>
> diff --git a/arch/mips/include/asm/pgtable-32.h b/arch/mips/include/asm/pgtable-32.h
> index 181bd8e..d21f3da 100644
> --- a/arch/mips/include/asm/pgtable-32.h
> +++ b/arch/mips/include/asm/pgtable-32.h
> @@ -103,7 +103,7 @@ static inline void pmd_clear(pmd_t *pmdp)
> pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
> }
>
> -#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +#if defined(CONFIG_XPA)
>
> #define pte_pfn(x) (((unsigned long)((x).pte_high >> _PFN_SHIFT)) | (unsigned long)((x).pte_low << _PAGE_PRESENT_SHIFT))
> static inline pte_t
> @@ -118,6 +118,20 @@ pfn_pte(unsigned long pfn, pgprot_t prot)
> return pte;
> }
>
> +#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +
> +#define pte_pfn(x) ((unsigned long)((x).pte_high >> 6))
> +
> +static inline pte_t pfn_pte(unsigned long pfn, pgprot_t prot)
> +{
> + pte_t pte;
> +
> + pte.pte_high = (pfn << 6) | (pgprot_val(prot) & 0x3f);
> + pte.pte_low = pgprot_val(prot);
> +
> + return pte;
> +}
> +
> #else
>
> #ifdef CONFIG_CPU_VR41XX
> @@ -166,7 +180,7 @@ pfn_pte(unsigned long pfn, pgprot_t prot)
>
> #else
>
> -#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +#if defined(CONFIG_XPA)
>
> /* Swap entries must have VALID and GLOBAL bits cleared. */
> #define __swp_type(x) (((x).val >> 4) & 0x1f)
> @@ -175,6 +189,15 @@ pfn_pte(unsigned long pfn, pgprot_t prot)
> #define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high })
> #define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val })
>
> +#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +
> +/* Swap entries must have VALID and GLOBAL bits cleared. */
> +#define __swp_type(x) (((x).val >> 2) & 0x1f)
> +#define __swp_offset(x) ((x).val >> 7)
> +#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 7) })
> +#define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_high })
> +#define __swp_entry_to_pte(x) ((pte_t) { 0, (x).val })
> +
> #else
> /*
> * Constraints:
> diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/pgtable-bits.h
> index 5bc663d..58e8bf8 100644
> --- a/arch/mips/include/asm/pgtable-bits.h
> +++ b/arch/mips/include/asm/pgtable-bits.h
> @@ -32,11 +32,11 @@
> * unpredictable things. The code (when it is written) to deal with
> * this problem will be in the update_mmu_cache() code for the r4k.
> */
> -#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +#if defined(CONFIG_XPA)
>
> /*
> - * Page table bit offsets used for 64 bit physical addressing on MIPS32,
> - * for example with Alchemy, Netlogic XLP/XLR or XPA.
> + * Page table bit offsets used for 64 bit physical addressing on
> + * MIPS32r5 with XPA.
> */
> enum pgtable_bits {
> /* Used by TLB hardware (placed in EntryLo*) */
> @@ -59,6 +59,27 @@ enum pgtable_bits {
> */
> #define _PFNX_MASK 0xffffff
>
> +#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +
> +/*
> + * Page table bit offsets used for 36 bit physical addressing on MIPS32,
> + * for example with Alchemy or Netlogic XLP/XLR.
> + */
> +enum pgtable_bits {
> + /* Used by TLB hardware (placed in EntryLo*) */
> + _PAGE_GLOBAL_SHIFT,
> + _PAGE_VALID_SHIFT,
> + _PAGE_DIRTY_SHIFT,
> + _CACHE_SHIFT,
> +
> + /* Used only by software (masked out before writing EntryLo*) */
> + _PAGE_PRESENT_SHIFT = _CACHE_SHIFT + 3,
> + _PAGE_NO_READ_SHIFT,
> + _PAGE_WRITE_SHIFT,
> + _PAGE_ACCESSED_SHIFT,
> + _PAGE_MODIFIED_SHIFT,
> +};
> +
> #elif defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
>
> /* Page table bits used for r3k systems */
> @@ -116,7 +137,7 @@ enum pgtable_bits {
> #endif
>
> /* Used by TLB hardware (placed in EntryLo*) */
> -#if (defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32))
> +#if defined(CONFIG_XPA)
> # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT)
> #elif defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6)
> # define _PAGE_NO_EXEC (cpu_has_rixi ? (1 << _PAGE_NO_EXEC_SHIFT) : 0)
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index 1459ee9..b83727d 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -130,7 +130,12 @@ do { \
>
> #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
>
> -#define pte_none(pte) (!(((pte).pte_high) & ~_PAGE_GLOBAL))
> +#ifdef CONFIG_XPA
> +# define pte_none(pte) (!(((pte).pte_high) & ~_PAGE_GLOBAL))
> +#else
> +# define pte_none(pte) (!(((pte).pte_low | (pte).pte_high) & ~_PAGE_GLOBAL))
> +#endif
> +
> #define pte_present(pte) ((pte).pte_low & _PAGE_PRESENT)
>
> static inline void set_pte(pte_t *ptep, pte_t pte)
> @@ -139,7 +144,11 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
> smp_wmb();
> ptep->pte_low = pte.pte_low;
>
> +#ifdef CONFIG_XPA
> if (pte.pte_high & _PAGE_GLOBAL) {
> +#else
> + if (pte.pte_low & _PAGE_GLOBAL) {
> +#endif
> pte_t *buddy = ptep_buddy(ptep);
> /*
> * Make sure the buddy is global too (if it's !none,
The XPA commit also removed
buddy->pte_low |= _PAGE_GLOBAL;
Does that need adding back in too for !CONFIG_XPA?
> @@ -157,7 +166,11 @@ static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *pt
>
> htw_stop();
> /* Preserve global status for the pair */
> +#ifdef CONFIG_XPA
> if (ptep_buddy(ptep)->pte_high & _PAGE_GLOBAL)
> +#else
> + if (ptep_buddy(ptep)->pte_low & _PAGE_GLOBAL)
> +#endif
same question
> null.pte_high = _PAGE_GLOBAL;
>
> set_pte_at(mm, addr, ptep, null);
> @@ -271,6 +284,8 @@ static inline int pte_young(pte_t pte) { return pte.pte_low & _PAGE_ACCESSED; }
> static inline pte_t pte_wrprotect(pte_t pte)
> {
> pte.pte_low &= ~_PAGE_WRITE;
> + if (!config_enabled(CONFIG_XPA))
> + pte.pte_low &= ~_PAGE_SILENT_WRITE;
> pte.pte_high &= ~_PAGE_SILENT_WRITE;
> return pte;
> }
> @@ -278,6 +293,8 @@ static inline pte_t pte_wrprotect(pte_t pte)
> static inline pte_t pte_mkclean(pte_t pte)
> {
> pte.pte_low &= ~_PAGE_MODIFIED;
> + if (!config_enabled(CONFIG_XPA))
> + pte.pte_low &= ~_PAGE_SILENT_WRITE;
> pte.pte_high &= ~_PAGE_SILENT_WRITE;
> return pte;
> }
> @@ -285,6 +302,8 @@ static inline pte_t pte_mkclean(pte_t pte)
> static inline pte_t pte_mkold(pte_t pte)
> {
> pte.pte_low &= ~_PAGE_ACCESSED;
> + if (!config_enabled(CONFIG_XPA))
> + pte.pte_low &= ~_PAGE_SILENT_READ;
> pte.pte_high &= ~_PAGE_SILENT_READ;
> return pte;
> }
similar question for pte_mkwrite, pte_mkdirty, pte_mkyoung?
Other than that it looks like a good revert to previous behaviour.
Cheers
James
> @@ -407,7 +426,7 @@ static inline pgprot_t pgprot_writecombine(pgprot_t _prot)
> */
> #define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
>
> -#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +#if defined(CONFIG_XPA)
> static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
> {
> pte.pte_low &= (_PAGE_MODIFIED | _PAGE_ACCESSED | _PFNX_MASK);
> @@ -416,6 +435,15 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
> pte.pte_high |= pgprot_val(newprot) & ~_PFN_MASK;
> return pte;
> }
> +#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
> +{
> + pte.pte_low &= _PAGE_CHG_MASK;
> + pte.pte_high &= (_PFN_MASK | _CACHE_MASK);
> + pte.pte_low |= pgprot_val(newprot);
> + pte.pte_high |= pgprot_val(newprot) & ~(_PFN_MASK | _CACHE_MASK);
> + return pte;
> +}
> #else
> static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
> {
> diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
> index 7e5fa09..0e57893 100644
> --- a/arch/mips/mm/init.c
> +++ b/arch/mips/mm/init.c
> @@ -98,8 +98,10 @@ static void *__kmap_pgprot(struct page *page, unsigned long addr, pgprot_t prot)
> idx += in_interrupt() ? FIX_N_COLOURS : 0;
> vaddr = __fix_to_virt(FIX_CMAP_END - idx);
> pte = mk_pte(page, prot);
> -#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> +#if defined(CONFIG_XPA)
> entrylo = pte_to_entrylo(pte.pte_high);
> +#elif defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> + entrylo = pte.pte_high;
> #else
> entrylo = pte_to_entrylo(pte_val(pte));
> #endif
> diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
> index 7e3272f..ceaee32 100644
> --- a/arch/mips/mm/tlbex.c
> +++ b/arch/mips/mm/tlbex.c
> @@ -1003,25 +1003,21 @@ static void build_get_ptep(u32 **p, unsigned int tmp, unsigned int ptr)
>
> static void build_update_entries(u32 **p, unsigned int tmp, unsigned int ptep)
> {
> - /*
> - * 64bit address support (36bit on a 32bit CPU) in a 32bit
> - * Kernel is a special case. Only a few CPUs use it.
> - */
> - if (config_enabled(CONFIG_PHYS_ADDR_T_64BIT) && !cpu_has_64bits) {
> + if (config_enabled(CONFIG_XPA)) {
> 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 */
>
> 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_lw(p, ptep, pte_off_odd, ptep); /* odd pte */
> + UASM_i_ROTR(p, ptep, ptep, ilog2(_PAGE_GLOBAL));
> 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);
> @@ -1030,7 +1026,22 @@ static void build_update_entries(u32 **p, unsigned int tmp, unsigned int ptep)
> uasm_i_and(p, ptep, scratch, ptep);
> uasm_i_mthc0(p, tmp, C0_ENTRYLO0);
> uasm_i_mthc0(p, ptep, C0_ENTRYLO1);
> -#endif
> + return;
> + }
> +
> + /*
> + * 64bit address support (36bit on a 32bit CPU) in a 32bit
> + * Kernel is a special case. Only a few CPUs use it.
> + */
> + if (config_enabled(CONFIG_PHYS_ADDR_T_64BIT) && !cpu_has_64bits) {
> + int pte_off_even = sizeof(pte_t) / 2;
> + int pte_off_odd = pte_off_even + sizeof(pte_t);
> +
> + uasm_i_lw(p, tmp, pte_off_even, ptep); /* even pte */
> + UASM_i_MTC0(p, tmp, C0_ENTRYLO0);
> +
> + uasm_i_lw(p, ptep, pte_off_odd, ptep); /* odd pte */
> + UASM_i_MTC0(p, ptep, C0_ENTRYLO1);
> return;
> }
>
> @@ -1524,7 +1535,7 @@ 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);
>
> - if (!cpu_has_64bits) {
> + if (config_enabled(CONFIG_XPA) && !cpu_has_64bits) {
> const int scratch = 1; /* Our extra working register */
>
> uasm_i_lui(p, scratch, (mode >> 16));
> --
> 2.8.0
>
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