在2023年10月4日十月 下午5:10，Gregory CLEMENT写道：
> From: Vladimir Kondratiev <vladimir.kondratiev@xxxxxxxxx>
>
> Now 64-bit MIPS uses 32-bit compatible segments KSEG0 and KSEG1
> to trivially map first 1/2 GByte of physical memory. This memory
> used to run kernel. This mean, one should have memory installed
> in this area in order for Linux to work.
>
> Kconfig CONFIG_USE_XKPHYS introduced; it adds support for kernel
> to use virtual addresses from the XKPHYS segment for both cached
> and uncached access. XKPHYS allows to access 2^48 bytes of
> memory, thus allowing kernel to work with any memory
> configuration.
>
> MIPS CPU sets KX bit in the CP0 status register at reset
> if RESET_BASE_MODE (BIT 1) set in the GCR_CL_RESET_BASE.
>
> Reset vector should fit into 32-bit. If reset vector put outside of
> KSEG1, BIT(1) should be set in this value.
>
> IRQ handler for CPU updated to generate 64-bit address for jump
Please use existing KBUILD_SYM32 symbol.
Thanks
- Jiaxun
>
> Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev@xxxxxxxxx>
> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
> ---
> arch/mips/Kconfig | 15 +++++++++++++
> arch/mips/Makefile | 4 ++++
> arch/mips/generic/Platform | 5 +++++
> arch/mips/include/asm/addrspace.h | 12 ++++++++--
> arch/mips/include/asm/mips-cm.h | 1 +
> arch/mips/include/asm/page.h | 10 +++++++++
> arch/mips/include/asm/vga.h | 4 ++++
> arch/mips/kernel/cps-vec.S | 8 +++++++
> arch/mips/kernel/genex.S | 14 ++++++++++++
> arch/mips/kernel/smp-cps.c | 37 +++++++++++++++++++++++--------
> arch/mips/kernel/traps.c | 32 +++++++++++++++++++++++---
> arch/mips/lib/uncached.c | 10 +++++++++
> arch/mips/mm/init.c | 4 ++--
> 13 files changed, 140 insertions(+), 16 deletions(-)
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index bc8421859006..92832bbcca5d 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -2026,6 +2026,21 @@ config 64BIT
>
> endchoice
>
> +config USE_XKPHYS
> + bool "use virtual address from XKPHYS"
> + depends on 64BIT
> + default n
> + help
> + By default, MIPS uses 32-bit compatible segments KSEG0 and KSEG1
> + to trivially map first 1/2 GByte of physical memory. This mean,
> + one should have memory installed in this area in order for Linux to
> + work. With this option selected, kernel uses virtual addresses from
> + the XKPHYS segment for both cached and uncached access. XKPHYS allows
> + to access 2^48 bytes of memory, thus allowing to work with any memory
> + configuration.
> +
> + Say N if not sure
> +
> config MIPS_VA_BITS_48
> bool "48 bits virtual memory"
> depends on 64BIT
> diff --git a/arch/mips/Makefile b/arch/mips/Makefile
> index f49807e1f19b..544ee8427cab 100644
> --- a/arch/mips/Makefile
> +++ b/arch/mips/Makefile
> @@ -303,6 +303,10 @@ ifdef CONFIG_64BIT
> endif
> endif
>
> + ifdef CONFIG_USE_XKPHYS
> + KBUILD_SYM32 = n
> + endif
> +
> ifeq ($(KBUILD_SYM32), y)
> cflags-$(KBUILD_SYM32) += -msym32 -DKBUILD_64BIT_SYM32
> else
> diff --git a/arch/mips/generic/Platform b/arch/mips/generic/Platform
> index 0c03623f3897..2be9947814ad 100644
> --- a/arch/mips/generic/Platform
> +++ b/arch/mips/generic/Platform
> @@ -12,7 +12,12 @@
> cflags-$(CONFIG_MACH_INGENIC_SOC) +=
> -I$(srctree)/arch/mips/include/asm/mach-ingenic
> cflags-$(CONFIG_MIPS_GENERIC) +=
> -I$(srctree)/arch/mips/include/asm/mach-generic
>
> +ifndef (CONFIG_USE_XKPHYS)
> load-$(CONFIG_MIPS_GENERIC) += 0xffffffff80100000
> +else
> +load-$(CONFIG_MIPS_GENERIC) += 0xa800000080100000
> +endif
> +
> all-$(CONFIG_MIPS_GENERIC) += vmlinux.gz.itb
>
> its-y := vmlinux.its.S
> diff --git a/arch/mips/include/asm/addrspace.h
> b/arch/mips/include/asm/addrspace.h
> index 59a48c60a065..8dc500d8e66d 100644
> --- a/arch/mips/include/asm/addrspace.h
> +++ b/arch/mips/include/asm/addrspace.h
> @@ -65,10 +65,15 @@
> #define XKSSEG _CONST64_(0x4000000000000000)
> #define XKPHYS _CONST64_(0x8000000000000000)
> #define XKSEG _CONST64_(0xc000000000000000)
> +#if !defined(CONFIG_USE_XKPHYS)
> #define CKSEG0 _CONST64_(0xffffffff80000000)
> #define CKSEG1 _CONST64_(0xffffffffa0000000)
> #define CKSSEG _CONST64_(0xffffffffc0000000)
> #define CKSEG3 _CONST64_(0xffffffffe0000000)
> +#else
> +#define CKSEG0 XKPHYS_CM_CACHED
> +#define CKSEG1 XKPHYS_CM_UNCACHED
> +#endif /* !defined(CONFIG_USE_XKPHYS) */
>
> #define CKSEG0ADDR(a) (CPHYSADDR(a) | CKSEG0)
> #define CKSEG1ADDR(a) (CPHYSADDR(a) | CKSEG1)
> @@ -126,8 +131,11 @@
> #define PHYS_TO_XKSEG_UNCACHED(p) PHYS_TO_XKPHYS(K_CALG_UNCACHED, (p))
> #define PHYS_TO_XKSEG_CACHED(p) PHYS_TO_XKPHYS(K_CALG_COH_SHAREABLE, (p))
> #define XKPHYS_TO_PHYS(p) ((p) & TO_PHYS_MASK)
> -#define PHYS_TO_XKPHYS(cm, a) (XKPHYS | (_ACAST64_(cm) << 59) | (a))
> -
> +#define XKPHYS_CM(cm) (XKPHYS | (_ACAST64_(cm) << 59))
> +#define PHYS_TO_XKPHYS(cm, a) (XKPHYS_CM(cm) | (a))
> +#define XKPHYS_CM_CACHED (XKPHYS_CM(K_CALG_COH_SHAREABLE))
> +#define XKPHYS_CM_UNCACHED (XKPHYS_CM(K_CALG_UNCACHED))
> +#define IS_XKPHYS(a) (((a) >> 62) == 2)
> /*
> * The ultimate limited of the 64-bit MIPS architecture: 2 bits for selecting
> * the region, 3 bits for the CCA mode. This leaves 59 bits of which the
> diff --git a/arch/mips/include/asm/mips-cm.h b/arch/mips/include/asm/mips-cm.h
> index 23c67c0871b1..15d8d69de455 100644
> --- a/arch/mips/include/asm/mips-cm.h
> +++ b/arch/mips/include/asm/mips-cm.h
> @@ -311,6 +311,7 @@ GCR_CX_ACCESSOR_RW(32, 0x018, other)
> /* GCR_Cx_RESET_BASE - Configure where powered up cores will fetch from */
> GCR_CX_ACCESSOR_RW(32, 0x020, reset_base)
> #define CM_GCR_Cx_RESET_BASE_BEVEXCBASE GENMASK(31, 12)
> +#define CM_GCR_Cx_RESET_BASE_MODE BIT(1)
>
> /* GCR_Cx_ID - Identify the current core */
> GCR_CX_ACCESSOR_RO(32, 0x028, id)
> diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
> index 5978a8dfb917..53b8306da571 100644
> --- a/arch/mips/include/asm/page.h
> +++ b/arch/mips/include/asm/page.h
> @@ -176,7 +176,11 @@ static inline unsigned long ___pa(unsigned long x)
> * the compatibility segements ckseg0 or ckseg1, or it may
> * be in xkphys.
> */
> +#if defined(CONFIG_USE_XKPHYS)
> + return XPHYSADDR(x);
> +#else
> return x < CKSEG0 ? XPHYSADDR(x) : CPHYSADDR(x);
> +#endif
> }
>
> if (!IS_ENABLED(CONFIG_EVA)) {
> @@ -196,7 +200,11 @@ static inline unsigned long ___pa(unsigned long x)
> return x - PAGE_OFFSET + PHYS_OFFSET;
> }
> #define __pa(x) ___pa((unsigned long)(x))
> +#if IS_ENABLED(CONFIG_64BIT) && IS_ENABLED(CONFIG_USE_XKPHYS)
> +#define __va(x) ((void *)PHYS_TO_XKSEG_CACHED(x))
> +#else
> #define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - PHYS_OFFSET))
> +#endif
> #include <asm/io.h>
>
> /*
> @@ -239,6 +247,8 @@ static inline unsigned long kaslr_offset(void)
> return __kaslr_offset;
> }
>
> +#define UNCAC_ADDR(addr) (UNCAC_BASE + __pa(addr))
> +
> #include <asm-generic/memory_model.h>
> #include <asm-generic/getorder.h>
>
> diff --git a/arch/mips/include/asm/vga.h b/arch/mips/include/asm/vga.h
> index 0136e0366698..e338e57d0784 100644
> --- a/arch/mips/include/asm/vga.h
> +++ b/arch/mips/include/asm/vga.h
> @@ -16,7 +16,11 @@
> * access the videoram directly without any black magic.
> */
>
> +#if defined(CONFIG_USE_XKPHYS)
> +#define VGA_MAP_MEM(x, s) UNCAC_ADDR(0x10000000L + (unsigned long)(x))
> +#else
> #define VGA_MAP_MEM(x, s) CKSEG1ADDR(0x10000000L + (unsigned long)(x))
> +#endif
>
> #define vga_readb(x) (*(x))
> #define vga_writeb(x, y) (*(y) = (x))
> diff --git a/arch/mips/kernel/cps-vec.S b/arch/mips/kernel/cps-vec.S
> index 64ecfdac6580..541f31a43a7f 100644
> --- a/arch/mips/kernel/cps-vec.S
> +++ b/arch/mips/kernel/cps-vec.S
> @@ -554,7 +554,11 @@ LEAF(mips_cps_cache_init)
> mul t1, t1, t0
> mul t1, t1, t2
>
> +#if defined(CONFIG_USE_XKPHYS)
> + PTR_LI a0, XKPHYS_CM_CACHED
> +#else
> li a0, CKSEG0
> +#endif
> PTR_ADD a1, a0, t1
> 1: cache Index_Store_Tag_I, 0(a0)
> PTR_ADD a0, a0, t0
> @@ -581,7 +585,11 @@ icache_done:
> mul t1, t1, t0
> mul t1, t1, t2
>
> +#if defined(CONFIG_USE_XKPHYS)
> + PTR_LI a0, XKPHYS_CM_CACHED
> +#else
> li a0, CKSEG0
> +#endif
> PTR_ADDU a1, a0, t1
> PTR_SUBU a1, a1, t0
> 1: cache Index_Store_Tag_D, 0(a0)
> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
> index b6de8e88c1bd..a002058e1838 100644
> --- a/arch/mips/kernel/genex.S
> +++ b/arch/mips/kernel/genex.S
> @@ -272,11 +272,25 @@ NESTED(except_vec_vi, 0, sp)
> .set push
> .set noreorder
> PTR_LA v1, except_vec_vi_handler
> +#if defined(CONFIG_USE_XKPHYS)
> +FEXPORT(except_vec_vi_63_48)
> + lui v0, 0 /* Patched - bits 63:48 */
> +FEXPORT(except_vec_vi_47_32)
> + ori v0, 0 /* Patched - bits 47:32 */
> + dsll v0, v0, 0x10
> +FEXPORT(except_vec_vi_31_16)
> + ori v0, 0 /* Patched - bits 31:16 */
> + dsll v0, v0, 0x10
> + jr v1
> +FEXPORT(except_vec_vi_15_0)
> + ori v0, 0 /* Patched - bits 15:0 */
> +#else /* defined(CONFIG_USE_XKPHYS) */
> FEXPORT(except_vec_vi_lui)
> lui v0, 0 /* Patched */
> jr v1
> FEXPORT(except_vec_vi_ori)
> ori v0, 0 /* Patched */
> +#endif /* defined(CONFIG_USE_XKPHYS) */
> .set pop
> END(except_vec_vi)
> EXPORT(except_vec_vi_end)
> diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
> index dd55d59b88db..47e76722a306 100644
> --- a/arch/mips/kernel/smp-cps.c
> +++ b/arch/mips/kernel/smp-cps.c
> @@ -34,10 +34,33 @@ static unsigned __init core_vpe_count(unsigned int
> cluster, unsigned core)
> return min(smp_max_threads, mips_cps_numvps(cluster, core));
> }
>
> +/**
> + * plat_core_entry - query reset vector for NMI/reset
> + *
> + * Returns low 32 bits of the reset vector
> + *
> + * This is used to fill 2 registers:
> + * - BEV Base (GCR_BEV_BASE) Offset: 0x0680
> + * - VP Local Reset Exception Base (GCR_CL_RESET_BASE,GCR_CO_RESET_BASE)
> + * Offset: 0x0020 (0x2020 relative to GCR_BASE_ADDR)
> + *
> + * In both registers, BIT(1) should be set in case it uses address in XKPHYS
> + * (as opposed to KSEG1). This bit defined as CM_GCR_Cx_RESET_BASE_MODE,
> + * using it unconditionally because for GCR_BEV_BASE its value is the same
> + */
> +static u32 plat_core_entry(void)
> +{
> +#if defined(CONFIG_USE_XKPHYS)
> + return (UNCAC_ADDR(mips_cps_core_entry) & 0xffffffff)
> + | CM_GCR_Cx_RESET_BASE_MODE;
> +#else
> + return CKSEG1ADDR((unsigned long)mips_cps_core_entry);
> +#endif
> +}
> +
> static void __init cps_smp_setup(void)
> {
> unsigned int nclusters, ncores, nvpes, core_vpes;
> - unsigned long core_entry;
> int cl, c, v;
>
> /* Detect & record VPE topology */
> @@ -94,10 +117,8 @@ static void __init cps_smp_setup(void)
> /* Make core 0 coherent with everything */
> write_gcr_cl_coherence(0xff);
>
> - if (mips_cm_revision() >= CM_REV_CM3) {
> - core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry);
> - write_gcr_bev_base(core_entry);
> - }
> + if (mips_cm_revision() >= CM_REV_CM3)
> + write_gcr_bev_base(plat_core_entry());
>
> #ifdef CONFIG_MIPS_MT_FPAFF
> /* If we have an FPU, enroll ourselves in the FPU-full mask */
> @@ -213,7 +234,7 @@ static void boot_core(unsigned int core, unsigned
> int vpe_id)
> mips_cm_lock_other(0, core, 0, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
>
> /* Set its reset vector */
> - write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));
> + write_gcr_co_reset_base(plat_core_entry());
>
> /* Ensure its coherency is disabled */
> write_gcr_co_coherence(0);
> @@ -290,7 +311,6 @@ static int cps_boot_secondary(int cpu, struct
> task_struct *idle)
> unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
> struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
> struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
> - unsigned long core_entry;
> unsigned int remote;
> int err;
>
> @@ -314,8 +334,7 @@ static int cps_boot_secondary(int cpu, struct
> task_struct *idle)
>
> if (cpu_has_vp) {
> mips_cm_lock_other(0, core, vpe_id, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
> - core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry);
> - write_gcr_co_reset_base(core_entry);
> + write_gcr_co_reset_base(plat_core_entry());
> mips_cm_unlock_other();
> }
>
> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
> index 246c6a6b0261..875594843626 100644
> --- a/arch/mips/kernel/traps.c
> +++ b/arch/mips/kernel/traps.c
> @@ -2091,11 +2091,20 @@ static void *set_vi_srs_handler(int n,
> vi_handler_t addr, int srs)
> * If no shadow set is selected then use the default handler
> * that does normal register saving and standard interrupt exit
> */
> - extern const u8 except_vec_vi[], except_vec_vi_lui[];
> - extern const u8 except_vec_vi_ori[], except_vec_vi_end[];
> + extern const u8 except_vec_vi[], except_vec_vi_end[];
> extern const u8 rollback_except_vec_vi[];
> const u8 *vec_start = using_rollback_handler() ?
> rollback_except_vec_vi : except_vec_vi;
> + const int handler_len = except_vec_vi_end - vec_start;
> +#if defined(CONFIG_USE_XKPHYS)
> + extern const u8 except_vec_vi_63_48[], except_vec_vi_47_32[];
> + extern const u8 except_vec_vi_31_16[], except_vec_vi_15_0[];
> + const int offset_63_48 = except_vec_vi_63_48 - vec_start;
> + const int offset_47_32 = except_vec_vi_47_32 - vec_start;
> + const int offset_31_16 = except_vec_vi_31_16 - vec_start;
> + const int offset_15_0 = except_vec_vi_15_0 - vec_start;
> +#else /* defined(CONFIG_USE_XKPHYS) */
> + extern const u8 except_vec_vi_lui[], except_vec_vi_ori[];
> #if defined(CONFIG_CPU_MICROMIPS) || defined(CONFIG_CPU_BIG_ENDIAN)
> const int lui_offset = except_vec_vi_lui - vec_start + 2;
> const int ori_offset = except_vec_vi_ori - vec_start + 2;
> @@ -2103,7 +2112,7 @@ static void *set_vi_srs_handler(int n,
> vi_handler_t addr, int srs)
> const int lui_offset = except_vec_vi_lui - vec_start;
> const int ori_offset = except_vec_vi_ori - vec_start;
> #endif
> - const int handler_len = except_vec_vi_end - vec_start;
> +#endif /* defined(CONFIG_USE_XKPHYS) */
>
> if (handler_len > VECTORSPACING) {
> /*
> @@ -2119,10 +2128,21 @@ static void *set_vi_srs_handler(int n,
> vi_handler_t addr, int srs)
> #else
> handler_len);
> #endif
> +#if defined(CONFIG_USE_XKPHYS)
> + h = (u16 *)(b + offset_63_48);
> + *h = (handler >> 48) & 0xffff;
> + h = (u16 *)(b + offset_47_32);
> + *h = (handler >> 32) & 0xffff;
> + h = (u16 *)(b + offset_31_16);
> + *h = (handler >> 16) & 0xffff;
> + h = (u16 *)(b + offset_15_0);
> + *h = (handler >> 0) & 0xffff;
> +#else /* defined(CONFIG_USE_XKPHYS) */
> h = (u16 *)(b + lui_offset);
> *h = (handler >> 16) & 0xffff;
> h = (u16 *)(b + ori_offset);
> *h = (handler & 0xffff);
> +#endif /* defined(CONFIG_USE_XKPHYS) */
> local_flush_icache_range((unsigned long)b,
> (unsigned long)(b+handler_len));
> }
> @@ -2332,7 +2352,11 @@ static const char panic_null_cerr[] =
> void set_uncached_handler(unsigned long offset, void *addr,
> unsigned long size)
> {
> +#if IS_ENABLED(CONFIG_64BIT) && IS_ENABLED(CONFIG_USE_XKPHYS)
> + unsigned long uncached_ebase = UNCAC_ADDR(ebase);
> +#else
> unsigned long uncached_ebase = CKSEG1ADDR(ebase);
> +#endif
>
> if (!addr)
> panic(panic_null_cerr);
> @@ -2384,9 +2408,11 @@ void __init trap_init(void)
> * EVA is special though as it allows segments to be rearranged
> * and to become uncached during cache error handling.
> */
> +#if !defined(CONFIG_USE_XKPHYS)
> if (!IS_ENABLED(CONFIG_EVA) && !WARN_ON(ebase_pa >= 0x20000000))
> ebase = CKSEG0ADDR(ebase_pa);
> else
> +#endif
> ebase = (unsigned long)phys_to_virt(ebase_pa);
> }
>
> diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c
> index f80a67c092b6..8a78348a2dd7 100644
> --- a/arch/mips/lib/uncached.c
> +++ b/arch/mips/lib/uncached.c
> @@ -44,6 +44,10 @@ unsigned long run_uncached(void *func)
>
> __asm__("move %0, $sp" : "=r" (sp));
>
> +#if defined(CONFIG_USE_XKPHYS)
> + if (IS_XKPHYS(sp))
> + usp = UNCAC_ADDR(sp);
> +#else /* defined(CONFIG_USE_XKPHYS) */
> if (sp >= (long)CKSEG0 && sp < (long)CKSEG2)
> usp = CKSEG1ADDR(sp);
> #ifdef CONFIG_64BIT
> @@ -52,10 +56,15 @@ unsigned long run_uncached(void *func)
> usp = PHYS_TO_XKPHYS(K_CALG_UNCACHED,
> XKPHYS_TO_PHYS((long long)sp));
> #endif
> +#endif /* defined(CONFIG_USE_XKPHYS) */
> else {
> BUG();
> usp = sp;
> }
> +#if defined(CONFIG_USE_XKPHYS)
> + if (IS_XKPHYS(lfunc))
> + ufunc = UNCAC_ADDR(lfunc);
> +#else /* defined(CONFIG_USE_XKPHYS) */
> if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2)
> ufunc = CKSEG1ADDR(lfunc);
> #ifdef CONFIG_64BIT
> @@ -64,6 +73,7 @@ unsigned long run_uncached(void *func)
> ufunc = PHYS_TO_XKPHYS(K_CALG_UNCACHED,
> XKPHYS_TO_PHYS((long long)lfunc));
> #endif
> +#endif /* defined(CONFIG_USE_XKPHYS) */
> else {
> BUG();
> ufunc = lfunc;
> diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
> index 5dcb525a8995..eb57283ec4e0 100644
> --- a/arch/mips/mm/init.c
> +++ b/arch/mips/mm/init.c
> @@ -427,7 +427,7 @@ void __init paging_init(void)
> free_area_init(max_zone_pfns);
> }
>
> -#ifdef CONFIG_64BIT
> +#if defined(CONFIG_64BIT) && !defined(CONFIG_USE_XKPHYS)
> static struct kcore_list kcore_kseg0;
> #endif
>
> @@ -470,7 +470,7 @@ void __init mem_init(void)
> setup_zero_pages(); /* Setup zeroed pages. */
> mem_init_free_highmem();
>
> -#ifdef CONFIG_64BIT
> +#if defined(CONFIG_64BIT) && !defined(CONFIG_USE_XKPHYS)
> if ((unsigned long) &_text > (unsigned long) CKSEG0)
> /* The -4 is a hack so that user tools don't have to handle
> the overflow. */
> --
> 2.40.1
--
- Jiaxun
