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: v5.15.108
Changes in v3: - Add missing SoB
Changes in v2: - Fix upstream commit line position
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 | 2 +- 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 | 68 ++++++++++++++++--------------- 5 files changed, 52 insertions(+), 40 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.
This patch had to be backported because: - the documentation for sv57 is not present here (as sv48/57 are not present) - handling of sv48/57 is not needed (as not present)
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 # 5.15.x Signed-off-by: Palmer Dabbelt palmer@rivosinc.com --- Documentation/riscv/vm-layout.rst | 2 +- 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 | 47 ++++++++++++++++++++++--------- 5 files changed, 49 insertions(+), 17 deletions(-)
diff --git a/Documentation/riscv/vm-layout.rst b/Documentation/riscv/vm-layout.rst index b7f98930d38d..a2ec11da38b0 100644 --- a/Documentation/riscv/vm-layout.rst +++ b/Documentation/riscv/vm-layout.rst @@ -48,7 +48,7 @@ RISC-V Linux Kernel SV39 ____________________________________________________________|___________________________________________________________ | | | | ffffffc000000000 | -256 GB | ffffffc7ffffffff | 32 GB | kasan - ffffffcefee00000 | -196 GB | ffffffcefeffffff | 2 MB | fixmap + ffffffcefea00000 | -196 GB | ffffffcefeffffff | 6 MB | fixmap ffffffceff000000 | -196 GB | ffffffceffffffff | 16 MB | PCI io ffffffcf00000000 | -196 GB | ffffffcfffffffff | 4 GB | vmemmap ffffffd000000000 | -192 GB | ffffffdfffffffff | 64 GB | vmalloc/ioremap space diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h index 54cbf07fb4e9..8839cd2b28d1 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_TEXT_POKE1, diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 39b550310ec6..397cb945b16e 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -66,9 +66,13 @@
#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 14b84d09354a..f874fe07fb78 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -291,7 +291,6 @@ 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 830f53b141a0..3f62ff02efc4 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -49,7 +49,6 @@ 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;
@@ -216,6 +215,14 @@ 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 @@ -265,7 +272,6 @@ 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 pmd_t __maybe_unused early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
#ifdef CONFIG_XIP_KERNEL #define riscv_pfn_base (*(unsigned long *)XIP_FIXUP(&riscv_pfn_base)) @@ -580,24 +586,28 @@ 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) ? (uintptr_t)early_dtb_pmd : pa, - PGDIR_SIZE, - IS_ENABLED(CONFIG_64BIT) ? PAGE_TABLE : PAGE_KERNEL); +#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 @@ -685,7 +695,8 @@ 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 @@ -735,6 +746,16 @@ static void __init setup_vm_final(void) pt_ops.get_pmd_virt = get_pmd_virt_fixmap; #endif /* 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 # 5.15.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 f874fe07fb78..8cc147491c67 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -286,10 +286,7 @@ 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 # 5.15.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 3f62ff02efc4..e800d7981e99 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -229,25 +229,8 @@ 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))
linux-stable-mirror@lists.linaro.org
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Alexandre Ghiti