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([94.75.70.14]) by smtp.gmail.com with ESMTPSA id 8-20020ac24828000000b004f26aabbd6asm961120lft.130.2023.05.22.05.18.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 May 2023 05:18:50 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d03079d2-f89a-11ed-b22d-6b7b168915f2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1684757931; x=1687349931; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2gkL2Is8EvWZRGU8xS7LanP8IxE/MMMODsHGbdZf8Xk=; b=JpcvJoFHdWG09xlp9yDLDMTIiMNTjKd7qDhBPNRseqJyZRgTjHky6BP3rljrKV6sFv bGc0Lchmn1L1oG0HDMi3v2RMmcPxNIflCoq9FjHTrPGwtDpBZ8N6ErL9yMWpJmSd7/wm eVoear/p0AKJLyT1x++hnf29qbrApsCLG/6saKQimAX6lGZlkKR+USIMqMU3+7NXDR/g jcDKuP4y7uwXVj6wmj9lBRKAMQdscgOCNaTdI1k023p6oOOWC3hToTctIND2JAecXjth 1b4K8D/PPzNMD0vzFZNDe06HbXTSr/ii7x2ZzUpHjqTXkkA03NA2gCSkryIkPFMsYsfA C/Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684757931; x=1687349931; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2gkL2Is8EvWZRGU8xS7LanP8IxE/MMMODsHGbdZf8Xk=; b=NfQwIpSnLvpQZt+mBJP8yKrA4CiVNR9rkLZT8J/Snrd+ZOxmiPePbJEGu4JGEng+xb MaP/k0broE0aoWAGiELypDQJZ+gpJVPuPTIPsR5cP3GJjxfRpx6/0tIB+T19agGNrRBQ H8PK7QXdvxDGbyeGu2MOcEPxbvmqbJAZ1ui8OxLbPA9q8YH9dBJL/poK/bdUYsftufMB l5GGG77UMYVbfIZPitMJ3PtLlhXddJQPshYaUle7pcFEJ5BgRi21LNV+Q6mZXGeh3Kj7 Cjqmchvh4sOMsRUmFTqI9Wmwvf8pm5bsUrBNrNktNdwu51yviFp1U0dkvLfMm36GUsZ0 bjig== X-Gm-Message-State: AC+VfDy2UA9/ZG0UbixoL6aIknHMThzCPOF33xlS6USfS5KTt28NkjOq ZeDoOZgnxhzzO5ATCeoWNGL0k6CC4kA= X-Google-Smtp-Source: ACHHUZ6Y238XM+k0mmlNYiSZdjpSBGGIuTYeuz61LINpSjhIWdGKYdD67wrNLnu1gUE6IyXf7HcYMA== X-Received: by 2002:a05:6512:14e:b0:4f3:a7ff:60b9 with SMTP id m14-20020a056512014e00b004f3a7ff60b9mr3368806lfo.67.1684757930862; Mon, 22 May 2023 05:18:50 -0700 (PDT) From: Oleksii Kurochko To: xen-devel@lists.xenproject.org Cc: Julien Grall , Jan Beulich , Andrew Cooper , Stefano Stabellini , Oleksii Kurochko , Bob Eshleman , Alistair Francis , Connor Davis Subject: [PATCH v8 2/5] xen/riscv: introduce setup_initial_pages Date: Mon, 22 May 2023 15:18:43 +0300 Message-Id: X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1684757969645100001 Content-Type: text/plain; charset="utf-8" The idea was taken from xvisor but the following changes were done: * Use only a minimal part of the code enough to enable MMU * rename {_}setup_initial_pagetables functions * add an argument for setup_initial_mapping to have an opportunity to make set PTE flags. * update setup_initial_pagetables function to map sections with correct PTE flags. * Rewrite enable_mmu() to C. * map linker addresses range to load addresses range without 1:1 mapping. It will be 1:1 only in case when load_start_addr is equal to linker_start_addr. * add safety checks such as: * Xen size is less than page size * linker addresses range doesn't overlap load addresses range * Rework macros {THIRD,SECOND,FIRST,ZEROETH}_{SHIFT,MASK} * change PTE_LEAF_DEFAULT to RW instead of RWX. * Remove phys_offset as it is not used now * Remove alignment of {map, pa}_start &=3D XEN_PT_LEVEL_MAP_MASK(0); in setup_inital_mapping() as they should be already aligned. Make a check that {map_pa}_start are aligned. * Remove clear_pagetables() as initial pagetables will be zeroed during bss initialization * Remove __attribute__((section(".entry")) for setup_initial_pagetables() as there is no such section in xen.lds.S * Update the argument of pte_is_valid() to "const pte_t *p" * Add check that Xen's load address is aligned at 4k boundary * Refactor setup_initial_pagetables() so it is mapping linker address range to load address range. After setup needed permissions for specific section ( such as .text, .rodata, etc ) otherwise RW permission will be set by default. * Add function to check that requested SATP_MODE is supported Origin: git@github.com:xvisor/xvisor.git 9be2fdd7 Signed-off-by: Oleksii Kurochko Reviewed-by: Jan Beulich --- Changes in V8: - Add parentheses for lvl in pt_index() macros. - introduce macros paddr_to_pfn() and pfn_to_paddr() and use them inside paddr_to_pte()/pte_to_paddr(). - Remove "__" in sfence_vma() and add blanks inside the parentheses of asm volatile. - Parenthesize the two & against the || at the start of setup_initial_mapp= ing() function. - Code style fixes. --- Changes in V7: - define CONFIG_PAGING_LEVELS=3D2 for SATP_MODE_SV32. - update switch_stack_and_jump macros(): add constraint 'X' for fn, memory clobber and wrap into do {} while ( false ). - add noreturn to definition of enable_mmu(). - update pt_index() to "(pt_linear_offset(lvl, (va)) & VPN_MASK)". - expand macros pte_to_addr()/addr_to_pte() in paddr_to_pte() and pte_to_paddr() functions and after drop them. - remove inclusion of . - update commit message around definition of PGTBL_INITIAL_COUNT. - remove PGTBL_ENTRY_AMOUNT and use PAGETABLE_ENTRIES instead. - code style fixes - remove permission argument of setup_initial_mapping() function - remove calc_pgtbl_lvls_num() as it's not needed anymore after definition of CONFIG_PAGING_LEVELS. - introduce sfence_vma(). - remove satp_mode argument from check_pgtbl_mode_support() and use RV_STAGE1_MODE directly instead. - change .align to .p2align. - drop inclusion of from head.S. This change isn't necessary for the current patch series. --- Changes in V6: - move PAGE_SHIFT, PADDR_BITS to the top of page-bits.h - cast argument x of pte_to_addr() macros to paddr_t to avoid risk of ove= rflow for RV32 - update type of num_levels from 'unsigned long' to 'unsigned int' - define PGTBL_INITIAL_COUNT as ((CONFIG_PAGING_LEVELS - 1) + 1) - update type of permission arguments. changed it from 'unsgined long' to= 'unsigned int' - fix code style - switch while 'loop' to 'for' loop - undef HANDLE_PGTBL - clean root page table after MMU is disabled in check_pgtbl_mode_support= () function - align __bss_start properly - remove unnecesssary const for paddr_to_pte, pte_to_paddr, pte_is_valid = functions - add switch_stack_and_jump macros and use it inside enable_mmu() before = jump to cont_after_mmu_is_enabled() function --- Changes in V5: * Indent fields of pte_t struct * Rename addr_to_pte() and ppn_to_paddr() to match their content --- Changes in V4: * use GB() macros instead of defining SZ_1G * hardcode XEN_VIRT_START and add comment (ADDRESS_SPACE_END + 1 - GB(1)) * remove unnecessary 'asm' word at the end of #error * encapsulate pte_t definition in a struct * rename addr_to_ppn() to ppn_to_paddr(). * change type of paddr argument from const unsigned long to paddr_t * pte_to_paddr() update prototype. * calculate size of Xen binary based on an amount of page tables * use unsgined int instead of 'uint32_t' instead of uint32_t as their use isn't warranted. * remove extern of bss_{start,end} as they aren't used in mm.c anymore * fix code style * add argument for HANDLE_PGTBL macros instead of curr_lvl_num variable * make enable_mmu() as noinline to prevent under link-time optimization because of the nature of enable_mmu() * add function to check that SATP_MODE is supported. * update the commit message * update setup_initial_pagetables to set correct PTE flags in one pass instead of calling setup_pte_permissions after setup_initial_pagetables= () as setup_initial_pagetables() isn't used to change permission flags. --- Changes in V3: - update definition of pte_t structure to have a proper size of pte_t in case of RV32. - update asm/mm.h with new functions and remove unnecessary 'extern'. - remove LEVEL_* macros as only XEN_PT_LEVEL_* are enough. - update paddr_to_pte() to receive permissions as an argument. - add check that map_start & pa_start is properly aligned. - move defines PAGETABLE_ORDER, PAGETABLE_ENTRIES, PTE_PPN_SHIFT to - Rename PTE_SHIFT to PTE_PPN_SHIFT - refactor setup_initial_pagetables: map all LINK addresses to LOAD addres= ses and after setup PTEs permission for sections; update check that linker and load addresses don't overlap. - refactor setup_initial_mapping: allocate pagetable 'dynamically' if it is necessary. - rewrite enable_mmu in C; add the check that map_start and pa_start are aligned on 4k boundary. - update the comment for setup_initial_pagetable funcion - Add RV_STAGE1_MODE to support different MMU modes - set XEN_VIRT_START very high to not overlap with load address range - align bss section --- Changes in V2: * update the commit message: * Remove {ZEROETH,FIRST,...}_{SHIFT,MASK, SIZE,...} and introduce instead of them XEN_PT_LEVEL_*() and LEVEL_* * Rework pt_linear_offset() and pt_index based on XEN_PT_LEVEL_*() * Remove clear_pagetables() functions as pagetables were zeroed during .bss initialization * Rename _setup_initial_pagetables() to setup_initial_mapping() * Make PTE_DEFAULT equal to RX. * Update prototype of setup_initial_mapping(..., bool writable) ->=20 setup_initial_mapping(..., UL flags) =20 * Update calls of setup_initial_mapping according to new prototype * Remove unnecessary call of: _setup_initial_pagetables(..., load_addr_start, load_addr_end, load_addr= _start, ...) * Define index* in the loop of setup_initial_mapping * Remove attribute "__attribute__((section(".entry")))" for setup_initial_= pagetables() as we don't have such section * make arguments of paddr_to_pte() and pte_is_valid() as const. * make xen_second_pagetable static. * use instead of declaring extern unsigned long _stext, 0et= ext, _srodata, _erodata * update 'extern unsigned long __init_begin' to 'extern unsigned long __i= nit_begin[]' * use aligned() instead of "__attribute__((__aligned__(PAGE_SIZE)))" * set __section(".bss.page_aligned") for page tables arrays * fix identatations * Change '__attribute__((section(".entry")))' to '__init' * Remove phys_offset as it isn't used now. * Remove alignment of {map, pa}_start &=3D XEN_PT_LEVEL_MAP_MASK(0); in setup_inital_mapping() as they should be already aligned. * Remove clear_pagetables() as initial pagetables will be zeroed during bss initialization * Remove __attribute__((section(".entry")) for setup_initial_pagetables() as there is no such section in xen.lds.S * Update the argument of pte_is_valid() to "const pte_t *p" --- xen/arch/riscv/Makefile | 1 + xen/arch/riscv/include/asm/config.h | 14 +- xen/arch/riscv/include/asm/current.h | 11 + xen/arch/riscv/include/asm/mm.h | 14 ++ xen/arch/riscv/include/asm/page-bits.h | 10 + xen/arch/riscv/include/asm/page.h | 61 ++++++ xen/arch/riscv/include/asm/processor.h | 5 + xen/arch/riscv/mm.c | 277 +++++++++++++++++++++++++ xen/arch/riscv/setup.c | 11 + xen/arch/riscv/xen.lds.S | 3 + 10 files changed, 406 insertions(+), 1 deletion(-) create mode 100644 xen/arch/riscv/include/asm/current.h create mode 100644 xen/arch/riscv/include/asm/mm.h create mode 100644 xen/arch/riscv/include/asm/page.h create mode 100644 xen/arch/riscv/mm.c diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile index 443f6bf15f..956ceb02df 100644 --- a/xen/arch/riscv/Makefile +++ b/xen/arch/riscv/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_EARLY_PRINTK) +=3D early_printk.o obj-y +=3D entry.o +obj-y +=3D mm.o obj-$(CONFIG_RISCV_64) +=3D riscv64/ obj-y +=3D sbi.o obj-y +=3D setup.o diff --git a/xen/arch/riscv/include/asm/config.h b/xen/arch/riscv/include/a= sm/config.h index 57c1b33ee5..a7886a5ad3 100644 --- a/xen/arch/riscv/include/asm/config.h +++ b/xen/arch/riscv/include/asm/config.h @@ -75,12 +75,24 @@ name: #endif =20 -#define XEN_VIRT_START _AT(UL, 0x80200000) +#ifdef CONFIG_RISCV_64 +#define XEN_VIRT_START 0xFFFFFFFFC0000000 /* (_AC(-1, UL) + 1 - GB(1)) */ +#else +#error "RV32 isn't supported" +#endif =20 #define SMP_CACHE_BYTES (1 << 6) =20 #define STACK_SIZE PAGE_SIZE =20 +#ifdef CONFIG_RISCV_64 +#define CONFIG_PAGING_LEVELS 3 +#define RV_STAGE1_MODE SATP_MODE_SV39 +#else +#define CONFIG_PAGING_LEVELS 2 +#define RV_STAGE1_MODE SATP_MODE_SV32 +#endif + #endif /* __RISCV_CONFIG_H__ */ /* * Local variables: diff --git a/xen/arch/riscv/include/asm/current.h b/xen/arch/riscv/include/= asm/current.h new file mode 100644 index 0000000000..d87e6717e0 --- /dev/null +++ b/xen/arch/riscv/include/asm/current.h @@ -0,0 +1,11 @@ +#ifndef __ASM_CURRENT_H +#define __ASM_CURRENT_H + +#define switch_stack_and_jump(stack, fn) do { \ + asm volatile ( \ + "mv sp, %0\n" \ + "j " #fn :: "r" (stack), "X" (fn) : "memory" ); \ + unreachable(); \ +} while ( false ) + +#endif /* __ASM_CURRENT_H */ diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/m= m.h new file mode 100644 index 0000000000..64293eacee --- /dev/null +++ b/xen/arch/riscv/include/asm/mm.h @@ -0,0 +1,14 @@ +#ifndef _ASM_RISCV_MM_H +#define _ASM_RISCV_MM_H + +#include + +#define pfn_to_paddr(pfn) ((paddr_t)(pfn) << PAGE_SHIFT) +#define paddr_to_pfn(pa) ((unsigned long)((pa) >> PAGE_SHIFT)) + +void setup_initial_pagetables(void); + +void enable_mmu(void); +void cont_after_mmu_is_enabled(void); + +#endif /* _ASM_RISCV_MM_H */ diff --git a/xen/arch/riscv/include/asm/page-bits.h b/xen/arch/riscv/includ= e/asm/page-bits.h index 1801820294..4a3e33589a 100644 --- a/xen/arch/riscv/include/asm/page-bits.h +++ b/xen/arch/riscv/include/asm/page-bits.h @@ -4,4 +4,14 @@ #define PAGE_SHIFT 12 /* 4 KiB Pages */ #define PADDR_BITS 56 /* 44-bit PPN */ =20 +#ifdef CONFIG_RISCV_64 +#define PAGETABLE_ORDER (9) +#else /* CONFIG_RISCV_32 */ +#define PAGETABLE_ORDER (10) +#endif + +#define PAGETABLE_ENTRIES (1 << PAGETABLE_ORDER) + +#define PTE_PPN_SHIFT 10 + #endif /* __RISCV_PAGE_BITS_H__ */ diff --git a/xen/arch/riscv/include/asm/page.h b/xen/arch/riscv/include/asm= /page.h new file mode 100644 index 0000000000..8b7ba91017 --- /dev/null +++ b/xen/arch/riscv/include/asm/page.h @@ -0,0 +1,61 @@ +#ifndef _ASM_RISCV_PAGE_H +#define _ASM_RISCV_PAGE_H + +#include +#include + +#include +#include + +#define VPN_MASK ((unsigned long)(PAGETABLE_ENTRIES - 1= )) + +#define XEN_PT_LEVEL_ORDER(lvl) ((lvl) * PAGETABLE_ORDER) +#define XEN_PT_LEVEL_SHIFT(lvl) (XEN_PT_LEVEL_ORDER(lvl) + PAGE_SHIFT) +#define XEN_PT_LEVEL_SIZE(lvl) (_AT(paddr_t, 1) << XEN_PT_LEVEL_SHIFT= (lvl)) +#define XEN_PT_LEVEL_MAP_MASK(lvl) (~(XEN_PT_LEVEL_SIZE(lvl) - 1)) +#define XEN_PT_LEVEL_MASK(lvl) (VPN_MASK << XEN_PT_LEVEL_SHIFT(lvl)) + +#define PTE_VALID BIT(0, UL) +#define PTE_READABLE BIT(1, UL) +#define PTE_WRITABLE BIT(2, UL) +#define PTE_EXECUTABLE BIT(3, UL) +#define PTE_USER BIT(4, UL) +#define PTE_GLOBAL BIT(5, UL) +#define PTE_ACCESSED BIT(6, UL) +#define PTE_DIRTY BIT(7, UL) +#define PTE_RSW (BIT(8, UL) | BIT(9, UL)) + +#define PTE_LEAF_DEFAULT (PTE_VALID | PTE_READABLE | PTE_WRITAB= LE) +#define PTE_TABLE (PTE_VALID) + +/* Calculate the offsets into the pagetables for a given VA */ +#define pt_linear_offset(lvl, va) ((va) >> XEN_PT_LEVEL_SHIFT(lvl)) + +#define pt_index(lvl, va) (pt_linear_offset((lvl), (va)) & VPN_MASK) + +/* Page Table entry */ +typedef struct { +#ifdef CONFIG_RISCV_64 + uint64_t pte; +#else + uint32_t pte; +#endif +} pte_t; + +static inline pte_t paddr_to_pte(paddr_t paddr, + unsigned int permissions) +{ + return (pte_t) { .pte =3D (paddr_to_pfn(paddr) << PTE_PPN_SHIFT) | per= missions }; +} + +static inline paddr_t pte_to_paddr(pte_t pte) +{ + return pfn_to_paddr(pte.pte >> PTE_PPN_SHIFT); +} + +static inline bool pte_is_valid(pte_t p) +{ + return p.pte & PTE_VALID; +} + +#endif /* _ASM_RISCV_PAGE_H */ diff --git a/xen/arch/riscv/include/asm/processor.h b/xen/arch/riscv/includ= e/asm/processor.h index a71448e02e..6db681d805 100644 --- a/xen/arch/riscv/include/asm/processor.h +++ b/xen/arch/riscv/include/asm/processor.h @@ -69,6 +69,11 @@ static inline void die(void) wfi(); } =20 +static inline void sfence_vma(void) +{ + asm volatile ( "sfence.vma" ::: "memory" ); +} + #endif /* __ASSEMBLY__ */ =20 #endif /* _ASM_RISCV_PROCESSOR_H */ diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c new file mode 100644 index 0000000000..b7f50ec8a4 --- /dev/null +++ b/xen/arch/riscv/mm.c @@ -0,0 +1,277 @@ +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +struct mmu_desc { + unsigned int num_levels; + unsigned int pgtbl_count; + pte_t *next_pgtbl; + pte_t *pgtbl_base; +}; + +extern unsigned char cpu0_boot_stack[STACK_SIZE]; + +#define PHYS_OFFSET ((unsigned long)_start - XEN_VIRT_START) +#define LOAD_TO_LINK(addr) ((addr) - PHYS_OFFSET) +#define LINK_TO_LOAD(addr) ((addr) + PHYS_OFFSET) + + +/* + * It is expected that Xen won't be more then 2 MB. + * The check in xen.lds.S guarantees that. + * At least 3 page tables (in case of Sv39 ) are needed to cover 2 MB. + * One for each page level table with PAGE_SIZE =3D 4 Kb. + * + * One L0 page table can cover 2 MB(512 entries of one page table * PAGE_S= IZE). + * + * It might be needed one more page table in case when Xen load address + * isn't 2 MB aligned. + */ +#define PGTBL_INITIAL_COUNT ((CONFIG_PAGING_LEVELS - 1) + 1) + +pte_t __section(".bss.page_aligned") __aligned(PAGE_SIZE) +stage1_pgtbl_root[PAGETABLE_ENTRIES]; + +pte_t __section(".bss.page_aligned") __aligned(PAGE_SIZE) +stage1_pgtbl_nonroot[PGTBL_INITIAL_COUNT * PAGETABLE_ENTRIES]; + +#define HANDLE_PGTBL(curr_lvl_num) = \ + index =3D pt_index(curr_lvl_num, page_addr); = \ + if ( pte_is_valid(pgtbl[index]) ) = \ + { = \ + /* Find L{ 0-3 } table */ = \ + pgtbl =3D (pte_t *)pte_to_paddr(pgtbl[index]); = \ + } = \ + else = \ + { = \ + /* Allocate new L{0-3} page table */ = \ + if ( mmu_desc->pgtbl_count =3D=3D PGTBL_INITIAL_COUNT ) = \ + { = \ + early_printk("(XEN) No initial table available\n"); = \ + /* panic(), BUG() or ASSERT() aren't ready now. */ = \ + die(); = \ + } = \ + mmu_desc->pgtbl_count++; = \ + pgtbl[index] =3D paddr_to_pte((unsigned long)mmu_desc->next_pgtbl,= \ + PTE_VALID); = \ + pgtbl =3D mmu_desc->next_pgtbl; = \ + mmu_desc->next_pgtbl +=3D PAGETABLE_ENTRIES; = \ + } + +static void __init setup_initial_mapping(struct mmu_desc *mmu_desc, + unsigned long map_start, + unsigned long map_end, + unsigned long pa_start) +{ + unsigned int index; + pte_t *pgtbl; + unsigned long page_addr; + + if ( (unsigned long)_start % XEN_PT_LEVEL_SIZE(0) ) + { + early_printk("(XEN) Xen should be loaded at 4k boundary\n"); + die(); + } + + if ( (map_start & ~XEN_PT_LEVEL_MAP_MASK(0)) || + (pa_start & ~XEN_PT_LEVEL_MAP_MASK(0)) ) + { + early_printk("(XEN) map and pa start addresses should be aligned\n= "); + /* panic(), BUG() or ASSERT() aren't ready now. */ + die(); + } + + for ( page_addr =3D map_start; + page_addr < map_end; + page_addr +=3D XEN_PT_LEVEL_SIZE(0) ) + { + pgtbl =3D mmu_desc->pgtbl_base; + + switch ( mmu_desc->num_levels ) + { + case 4: /* Level 3 */ + HANDLE_PGTBL(3); + case 3: /* Level 2 */ + HANDLE_PGTBL(2); + case 2: /* Level 1 */ + HANDLE_PGTBL(1); + case 1: /* Level 0 */ + { + unsigned long paddr =3D (page_addr - map_start) + pa_start; + unsigned int permissions =3D PTE_LEAF_DEFAULT; + pte_t pte_to_be_written; + + index =3D pt_index(0, page_addr); + + if ( is_kernel_text(LINK_TO_LOAD(page_addr)) || + is_kernel_inittext(LINK_TO_LOAD(page_addr)) ) + permissions =3D + PTE_EXECUTABLE | PTE_READABLE | PTE_VALID; + + if ( is_kernel_rodata(LINK_TO_LOAD(page_addr)) ) + permissions =3D PTE_READABLE | PTE_VALID; + + pte_to_be_written =3D paddr_to_pte(paddr, permissions); + + if ( !pte_is_valid(pgtbl[index]) ) + pgtbl[index] =3D pte_to_be_written; + else + { + if ( (pgtbl[index].pte ^ pte_to_be_written.pte) & + ~(PTE_DIRTY | PTE_ACCESSED) ) + { + early_printk("PTE overridden has occurred\n"); + /* panic(), aren't ready now. */ + die(); + } + } + } + } + } +} +#undef HANDLE_PGTBL + +static bool __init check_pgtbl_mode_support(struct mmu_desc *mmu_desc, + unsigned long load_start) +{ + bool is_mode_supported =3D false; + unsigned int index; + unsigned int page_table_level =3D (mmu_desc->num_levels - 1); + unsigned level_map_mask =3D XEN_PT_LEVEL_MAP_MASK(page_table_level); + + unsigned long aligned_load_start =3D load_start & level_map_mask; + unsigned long aligned_page_size =3D XEN_PT_LEVEL_SIZE(page_table_level= ); + unsigned long xen_size =3D (unsigned long)(_end - start); + + if ( (load_start + xen_size) > (aligned_load_start + aligned_page_size= ) ) + { + early_printk("please place Xen to be in range of PAGE_SIZE " + "where PAGE_SIZE is XEN_PT_LEVEL_SIZE( {L3 | L2 | L1}= ) " + "depending on expected SATP_MODE \n" + "XEN_PT_LEVEL_SIZE is defined in \n"); + die(); + } + + index =3D pt_index(page_table_level, aligned_load_start); + stage1_pgtbl_root[index] =3D paddr_to_pte(aligned_load_start, + PTE_LEAF_DEFAULT | PTE_EXECUTA= BLE); + + sfence_vma(); + csr_write(CSR_SATP, + PFN_DOWN((unsigned long)stage1_pgtbl_root) | + RV_STAGE1_MODE << SATP_MODE_SHIFT); + + if ( (csr_read(CSR_SATP) >> SATP_MODE_SHIFT) =3D=3D RV_STAGE1_MODE ) + is_mode_supported =3D true; + + csr_write(CSR_SATP, 0); + + sfence_vma(); + + /* Clean MMU root page table */ + stage1_pgtbl_root[index] =3D paddr_to_pte(0x0, 0x0); + + return is_mode_supported; +} + +/* + * setup_initial_pagetables: + * + * Build the page tables for Xen that map the following: + * 1. Calculate page table's level numbers. + * 2. Init mmu description structure. + * 3. Check that linker addresses range doesn't overlap + * with load addresses range + * 4. Map all linker addresses and load addresses ( it shouldn't + * be 1:1 mapped and will be 1:1 mapped only in case if + * linker address is equal to load address ) with + * RW permissions by default. + * 5. Setup proper PTE permissions for each section. + */ +void __init setup_initial_pagetables(void) +{ + struct mmu_desc mmu_desc =3D { CONFIG_PAGING_LEVELS, 0, NULL, NULL }; + + /* + * Access to _start, _end is always PC-relative thereby when access + * them we will get load adresses of start and end of Xen. + * To get linker addresses LOAD_TO_LINK() is required to use. + */ + unsigned long load_start =3D (unsigned long)_start; + unsigned long load_end =3D (unsigned long)_end; + unsigned long linker_start =3D LOAD_TO_LINK(load_start); + unsigned long linker_end =3D LOAD_TO_LINK(load_end); + + if ( (linker_start !=3D load_start) && + (linker_start <=3D load_end) && (load_start <=3D linker_end) ) + { + early_printk("(XEN) linker and load address ranges overlap\n"); + die(); + } + + if ( !check_pgtbl_mode_support(&mmu_desc, load_start) ) + { + early_printk("requested MMU mode isn't supported by CPU\n" + "Please choose different in \n"); + die(); + } + + mmu_desc.pgtbl_base =3D stage1_pgtbl_root; + mmu_desc.next_pgtbl =3D stage1_pgtbl_nonroot; + + setup_initial_mapping(&mmu_desc, + linker_start, + linker_end, + load_start); +} + +void __init noreturn noinline enable_mmu() +{ + /* + * Calculate a linker time address of the mmu_is_enabled + * label and update CSR_STVEC with it. + * MMU is configured in a way where linker addresses are mapped + * on load addresses so in a case when linker addresses are not equal + * to load addresses, after MMU is enabled, it will cause + * an exception and jump to linker time addresses. + * Otherwise if load addresses are equal to linker addresses the code + * after mmu_is_enabled label will be executed without exception. + */ + csr_write(CSR_STVEC, LOAD_TO_LINK((unsigned long)&&mmu_is_enabled)); + + /* Ensure page table writes precede loading the SATP */ + sfence_vma(); + + /* Enable the MMU and load the new pagetable for Xen */ + csr_write(CSR_SATP, + PFN_DOWN((unsigned long)stage1_pgtbl_root) | + RV_STAGE1_MODE << SATP_MODE_SHIFT); + + asm volatile ( ".p2align 2" ); + mmu_is_enabled: + /* + * Stack should be re-inited as: + * 1. Right now an address of the stack is relative to load time + * addresses what will cause an issue in case of load start address + * isn't equal to linker start address. + * 2. Addresses in stack are all load time relative which can be an + * issue in case when load start address isn't equal to linker + * start address. + * + * We can't return to the caller because the stack was reseted + * and it may have stash some variable on the stack. + * Jump to a brand new function as the stack was reseted + */ + + switch_stack_and_jump((unsigned long)cpu0_boot_stack + STACK_SIZE, + cont_after_mmu_is_enabled); +} + diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c index 3786f337e0..315804aa87 100644 --- a/xen/arch/riscv/setup.c +++ b/xen/arch/riscv/setup.c @@ -2,6 +2,7 @@ #include =20 #include +#include =20 /* Xen stack for bringing up the first CPU. */ unsigned char __initdata cpu0_boot_stack[STACK_SIZE] @@ -26,3 +27,13 @@ void __init noreturn start_xen(unsigned long bootcpu_id, =20 unreachable(); } + +void __init noreturn cont_after_mmu_is_enabled(void) +{ + early_printk("All set up\n"); + + for ( ;; ) + asm volatile ("wfi"); + + unreachable(); +} diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S index 31e0d3576c..fe475d096d 100644 --- a/xen/arch/riscv/xen.lds.S +++ b/xen/arch/riscv/xen.lds.S @@ -172,3 +172,6 @@ ASSERT(IS_ALIGNED(__bss_end, POINTER_ALIGN), "__= bss_end is misaligned") =20 ASSERT(!SIZEOF(.got), ".got non-empty") ASSERT(!SIZEOF(.got.plt), ".got.plt non-empty") + +ASSERT(_end - _start <=3D MB(2), "Xen too large for early-boot assumptions= ") + --=20 2.40.1