We used to map the dtb differently between early_pg_dir and swapper_pg_dir which caused issues when we referenced addresses from the early mapping with swapper_pg_dir (reserved_mem): move the dtb mapping to the fixmap region in patch 1, which allows to simplify dtb handling in patch 2.
base-commit-tag: v6.2.11
Changes in v2: - Add missing SoB
Alexandre Ghiti (3): riscv: Move early dtb mapping into the fixmap region riscv: Do not set initial_boot_params to the linear address of the dtb riscv: No need to relocate the dtb as it lies in the fixmap region
Documentation/riscv/vm-layout.rst | 6 +-- arch/riscv/include/asm/fixmap.h | 8 +++ arch/riscv/include/asm/pgtable.h | 8 ++- arch/riscv/kernel/setup.c | 6 +-- arch/riscv/mm/init.c | 82 ++++++++++++++----------------- 5 files changed, 54 insertions(+), 56 deletions(-)
commit ef69d2559fe91f23d27a3d6fd640b5641787d22e upstream.
riscv establishes 2 virtual mappings:
- early_pg_dir maps the kernel which allows to discover the system memory - swapper_pg_dir installs the final mapping (linear mapping included)
We used to map the dtb in early_pg_dir using DTB_EARLY_BASE_VA, and this mapping was not carried over in swapper_pg_dir. It happens that early_init_fdt_scan_reserved_mem() must be called before swapper_pg_dir is setup otherwise we could allocate reserved memory defined in the dtb. And this function initializes reserved_mem variable with addresses that lie in the early_pg_dir dtb mapping: when those addresses are reused with swapper_pg_dir, this mapping does not exist and then we trap.
The previous "fix" was incorrect as early_init_fdt_scan_reserved_mem() must be called before swapper_pg_dir is set up otherwise we could allocate in reserved memory defined in the dtb.
So move the dtb mapping in the fixmap region which is established in early_pg_dir and handed over to swapper_pg_dir.
Fixes: 922b0375fc93 ("riscv: Fix memblock reservation for device tree blob") Fixes: 8f3a2b4a96dc ("RISC-V: Move DT mapping outof fixmap") Fixes: 50e63dd8ed92 ("riscv: fix reserved memory setup") Reported-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/all/f8e67f82-103d-156c-deb0-d6d6e2756f5e@microchip.c... Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Reviewed-by: Conor Dooley conor.dooley@microchip.com Tested-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/r/20230329081932.79831-2-alexghiti@rivosinc.com Cc: stable@vger.kernel.org # 6.2.x Signed-off-by: Palmer Dabbelt palmer@rivosinc.com --- Documentation/riscv/vm-layout.rst | 6 +-- arch/riscv/include/asm/fixmap.h | 8 ++++ arch/riscv/include/asm/pgtable.h | 8 +++- arch/riscv/kernel/setup.c | 1 - arch/riscv/mm/init.c | 61 +++++++++++++++++-------------- 5 files changed, 51 insertions(+), 33 deletions(-)
diff --git a/Documentation/riscv/vm-layout.rst b/Documentation/riscv/vm-layout.rst index 3be44e74ec5d..5462c84f4723 100644 --- a/Documentation/riscv/vm-layout.rst +++ b/Documentation/riscv/vm-layout.rst @@ -47,7 +47,7 @@ RISC-V Linux Kernel SV39 | Kernel-space virtual memory, shared between all processes: ____________________________________________________________|___________________________________________________________ | | | | - ffffffc6fee00000 | -228 GB | ffffffc6feffffff | 2 MB | fixmap + ffffffc6fea00000 | -228 GB | ffffffc6feffffff | 6 MB | fixmap ffffffc6ff000000 | -228 GB | ffffffc6ffffffff | 16 MB | PCI io ffffffc700000000 | -228 GB | ffffffc7ffffffff | 4 GB | vmemmap ffffffc800000000 | -224 GB | ffffffd7ffffffff | 64 GB | vmalloc/ioremap space @@ -83,7 +83,7 @@ RISC-V Linux Kernel SV48 | Kernel-space virtual memory, shared between all processes: ____________________________________________________________|___________________________________________________________ | | | | - ffff8d7ffee00000 | -114.5 TB | ffff8d7ffeffffff | 2 MB | fixmap + ffff8d7ffea00000 | -114.5 TB | ffff8d7ffeffffff | 6 MB | fixmap ffff8d7fff000000 | -114.5 TB | ffff8d7fffffffff | 16 MB | PCI io ffff8d8000000000 | -114.5 TB | ffff8f7fffffffff | 2 TB | vmemmap ffff8f8000000000 | -112.5 TB | ffffaf7fffffffff | 32 TB | vmalloc/ioremap space @@ -119,7 +119,7 @@ RISC-V Linux Kernel SV57 | Kernel-space virtual memory, shared between all processes: ____________________________________________________________|___________________________________________________________ | | | | - ff1bfffffee00000 | -57 PB | ff1bfffffeffffff | 2 MB | fixmap + ff1bfffffea00000 | -57 PB | ff1bfffffeffffff | 6 MB | fixmap ff1bffffff000000 | -57 PB | ff1bffffffffffff | 16 MB | PCI io ff1c000000000000 | -57 PB | ff1fffffffffffff | 1 PB | vmemmap ff20000000000000 | -56 PB | ff5fffffffffffff | 16 PB | vmalloc/ioremap space diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h index 5c3e7b97fcc6..0a55099bb734 100644 --- a/arch/riscv/include/asm/fixmap.h +++ b/arch/riscv/include/asm/fixmap.h @@ -22,6 +22,14 @@ */ enum fixed_addresses { FIX_HOLE, + /* + * The fdt fixmap mapping must be PMD aligned and will be mapped + * using PMD entries in fixmap_pmd in 64-bit and a PGD entry in 32-bit. + */ + FIX_FDT_END, + FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1, + + /* Below fixmaps will be mapped using fixmap_pte */ FIX_PTE, FIX_PMD, FIX_PUD, diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 6da0f3285dd2..f1ef0c3f905a 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -87,9 +87,13 @@
#define FIXADDR_TOP PCI_IO_START #ifdef CONFIG_64BIT -#define FIXADDR_SIZE PMD_SIZE +#define MAX_FDT_SIZE PMD_SIZE +#define FIX_FDT_SIZE (MAX_FDT_SIZE + SZ_2M) +#define FIXADDR_SIZE (PMD_SIZE + FIX_FDT_SIZE) #else -#define FIXADDR_SIZE PGDIR_SIZE +#define MAX_FDT_SIZE PGDIR_SIZE +#define FIX_FDT_SIZE MAX_FDT_SIZE +#define FIXADDR_SIZE (PGDIR_SIZE + FIX_FDT_SIZE) #endif #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 86acd690d529..ef98db2826fc 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -283,7 +283,6 @@ void __init setup_arch(char **cmdline_p) else pr_err("No DTB found in kernel mappings\n"); #endif - early_init_fdt_scan_reserved_mem(); misc_mem_init();
init_resources(); diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 478d6763a01a..fb78d6bbabae 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -57,7 +57,6 @@ unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] EXPORT_SYMBOL(empty_zero_page);
extern char _start[]; -#define DTB_EARLY_BASE_VA PGDIR_SIZE void *_dtb_early_va __initdata; uintptr_t _dtb_early_pa __initdata;
@@ -236,6 +235,14 @@ static void __init setup_bootmem(void) set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
reserve_initrd_mem(); + + /* + * No allocation should be done before reserving the memory as defined + * in the device tree, otherwise the allocation could end up in a + * reserved region. + */ + early_init_fdt_scan_reserved_mem(); + /* * If DTB is built in, no need to reserve its memblock. * Otherwise, do reserve it but avoid using @@ -279,9 +286,6 @@ pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss; static pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); -static p4d_t __maybe_unused early_dtb_p4d[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE); -static pud_t __maybe_unused early_dtb_pud[PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE); -static pmd_t __maybe_unused early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
#ifdef CONFIG_XIP_KERNEL #define pt_ops (*(struct pt_alloc_ops *)XIP_FIXUP(&pt_ops)) @@ -626,9 +630,6 @@ static void __init create_p4d_mapping(p4d_t *p4dp, #define trampoline_pgd_next (pgtable_l5_enabled ? \ (uintptr_t)trampoline_p4d : (pgtable_l4_enabled ? \ (uintptr_t)trampoline_pud : (uintptr_t)trampoline_pmd)) -#define early_dtb_pgd_next (pgtable_l5_enabled ? \ - (uintptr_t)early_dtb_p4d : (pgtable_l4_enabled ? \ - (uintptr_t)early_dtb_pud : (uintptr_t)early_dtb_pmd)) #else #define pgd_next_t pte_t #define alloc_pgd_next(__va) pt_ops.alloc_pte(__va) @@ -636,7 +637,6 @@ static void __init create_p4d_mapping(p4d_t *p4dp, #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot) \ create_pte_mapping(__nextp, __va, __pa, __sz, __prot) #define fixmap_pgd_next ((uintptr_t)fixmap_pte) -#define early_dtb_pgd_next ((uintptr_t)early_dtb_pmd) #define create_p4d_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0) #define create_pud_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0) #define create_pmd_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0) @@ -860,32 +860,28 @@ static void __init create_kernel_page_table(pgd_t *pgdir, bool early) * this means 2 PMD entries whereas for 32-bit kernel, this is only 1 PGDIR * entry. */ -static void __init create_fdt_early_page_table(pgd_t *pgdir, uintptr_t dtb_pa) +static void __init create_fdt_early_page_table(pgd_t *pgdir, + uintptr_t fix_fdt_va, + uintptr_t dtb_pa) { -#ifndef CONFIG_BUILTIN_DTB uintptr_t pa = dtb_pa & ~(PMD_SIZE - 1);
- create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA, - IS_ENABLED(CONFIG_64BIT) ? early_dtb_pgd_next : pa, - PGDIR_SIZE, - IS_ENABLED(CONFIG_64BIT) ? PAGE_TABLE : PAGE_KERNEL); - - if (pgtable_l5_enabled) - create_p4d_mapping(early_dtb_p4d, DTB_EARLY_BASE_VA, - (uintptr_t)early_dtb_pud, P4D_SIZE, PAGE_TABLE); - - if (pgtable_l4_enabled) - create_pud_mapping(early_dtb_pud, DTB_EARLY_BASE_VA, - (uintptr_t)early_dtb_pmd, PUD_SIZE, PAGE_TABLE); +#ifndef CONFIG_BUILTIN_DTB + /* Make sure the fdt fixmap address is always aligned on PMD size */ + BUILD_BUG_ON(FIX_FDT % (PMD_SIZE / PAGE_SIZE));
- if (IS_ENABLED(CONFIG_64BIT)) { - create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA, + /* In 32-bit only, the fdt lies in its own PGD */ + if (!IS_ENABLED(CONFIG_64BIT)) { + create_pgd_mapping(early_pg_dir, fix_fdt_va, + pa, MAX_FDT_SIZE, PAGE_KERNEL); + } else { + create_pmd_mapping(fixmap_pmd, fix_fdt_va, pa, PMD_SIZE, PAGE_KERNEL); - create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE, + create_pmd_mapping(fixmap_pmd, fix_fdt_va + PMD_SIZE, pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL); }
- dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1)); + dtb_early_va = (void *)fix_fdt_va + (dtb_pa & (PMD_SIZE - 1)); #else /* * For 64-bit kernel, __va can't be used since it would return a linear @@ -1055,7 +1051,8 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) create_kernel_page_table(early_pg_dir, true);
/* Setup early mapping for FDT early scan */ - create_fdt_early_page_table(early_pg_dir, dtb_pa); + create_fdt_early_page_table(early_pg_dir, + __fix_to_virt(FIX_FDT), dtb_pa);
/* * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap @@ -1097,6 +1094,16 @@ static void __init setup_vm_final(void) u64 i;
/* Setup swapper PGD for fixmap */ +#if !defined(CONFIG_64BIT) + /* + * In 32-bit, the device tree lies in a pgd entry, so it must be copied + * directly in swapper_pg_dir in addition to the pgd entry that points + * to fixmap_pte. + */ + unsigned long idx = pgd_index(__fix_to_virt(FIX_FDT)); + + set_pgd(&swapper_pg_dir[idx], early_pg_dir[idx]); +#endif create_pgd_mapping(swapper_pg_dir, FIXADDR_START, __pa_symbol(fixmap_pgd_next), PGDIR_SIZE, PAGE_TABLE);
commit f1581626071c8e37c58c5e8f0b4126b17172a211 upstream.
early_init_dt_verify() is already called in parse_dtb() and since the dtb address does not change anymore (it is now in the fixmap region), no need to reset initial_boot_params by calling early_init_dt_verify() again.
Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Link: https://lore.kernel.org/r/20230329081932.79831-3-alexghiti@rivosinc.com Cc: stable@vger.kernel.org # 6.2.x Signed-off-by: Palmer Dabbelt palmer@rivosinc.com --- arch/riscv/kernel/setup.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index ef98db2826fc..2acf51c23567 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -278,10 +278,7 @@ void __init setup_arch(char **cmdline_p) #if IS_ENABLED(CONFIG_BUILTIN_DTB) unflatten_and_copy_device_tree(); #else - if (early_init_dt_verify(__va(XIP_FIXUP(dtb_early_pa)))) - unflatten_device_tree(); - else - pr_err("No DTB found in kernel mappings\n"); + unflatten_device_tree(); #endif misc_mem_init();
commit 1b50f956c8fe9082bdee4a9cfd798149c52f7043 upstream.
We used to access the dtb via its linear mapping address but now that the dtb early mapping was moved in the fixmap region, we can keep using this address since it is present in swapper_pg_dir, and remove the dtb relocation.
Note that the relocation was wrong anyway since early_memremap() is restricted to 256K whereas the maximum fdt size is 2MB.
Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Reviewed-by: Conor Dooley conor.dooley@microchip.com Tested-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/r/20230329081932.79831-4-alexghiti@rivosinc.com Cc: stable@vger.kernel.org # 6.2.x Signed-off-by: Palmer Dabbelt palmer@rivosinc.com --- arch/riscv/mm/init.c | 21 ++------------------- 1 file changed, 2 insertions(+), 19 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index fb78d6bbabae..0f14f4a8d179 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -249,25 +249,8 @@ static void __init setup_bootmem(void) * early_init_fdt_reserve_self() since __pa() does * not work for DTB pointers that are fixmap addresses */ - if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) { - /* - * In case the DTB is not located in a memory region we won't - * be able to locate it later on via the linear mapping and - * get a segfault when accessing it via __va(dtb_early_pa). - * To avoid this situation copy DTB to a memory region. - * Note that memblock_phys_alloc will also reserve DTB region. - */ - if (!memblock_is_memory(dtb_early_pa)) { - size_t fdt_size = fdt_totalsize(dtb_early_va); - phys_addr_t new_dtb_early_pa = memblock_phys_alloc(fdt_size, PAGE_SIZE); - void *new_dtb_early_va = early_memremap(new_dtb_early_pa, fdt_size); - - memcpy(new_dtb_early_va, dtb_early_va, fdt_size); - early_memunmap(new_dtb_early_va, fdt_size); - _dtb_early_pa = new_dtb_early_pa; - } else - memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); - } + if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) + memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
dma_contiguous_reserve(dma32_phys_limit); if (IS_ENABLED(CONFIG_64BIT))
On Fri, Apr 28, 2023 at 12:37:42PM +0200, Alexandre Ghiti wrote:
We used to map the dtb differently between early_pg_dir and swapper_pg_dir which caused issues when we referenced addresses from the early mapping with swapper_pg_dir (reserved_mem): move the dtb mapping to the fixmap region in patch 1, which allows to simplify dtb handling in patch 2.
base-commit-tag: v6.2.11
Thanks for redoing all of these, now queued up!
greg k-h
On Fri, Apr 28, 2023 at 01:15:35PM +0200, Greg KH wrote:
On Fri, Apr 28, 2023 at 12:37:42PM +0200, Alexandre Ghiti wrote:
We used to map the dtb differently between early_pg_dir and swapper_pg_dir which caused issues when we referenced addresses from the early mapping with swapper_pg_dir (reserved_mem): move the dtb mapping to the fixmap region in patch 1, which allows to simplify dtb handling in patch 2.
base-commit-tag: v6.2.11
Thanks for redoing all of these, now queued up!
Aye, thanks for both that & for doing the fixmap stuff in the first place Alex :)
Cheers, Conor.
linux-stable-mirror@lists.linaro.org
-
Alexandre Ghiti -
Conor Dooley -
Greg KH