[PW_SID:1153951] riscv: document the Sv32 virtual memory layout - #2551
[PW_SID:1153951] riscv: document the Sv32 virtual memory layout#2551linux-riscv-bot wants to merge 9 commits into
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…_RWX When CONFIG_STRICT_MODULE_RWX is not set, execmem cannot create temporary writable mappings for read-only executable pages. In this case, the execmem ranges must already have writable permissions. Currently EXECMEM_KPROBES unconditionally uses PAGE_KERNEL_READ_EXEC, which causes kprobe instruction slot writes to trigger page faults on systems where CONFIG_STRICT_MODULE_RWX is not enabled. Fix this by using PAGE_KERNEL_EXEC when CONFIG_STRICT_MODULE_RWX is not available. Signed-off-by: Xiaofeng Yuan <xiaofengmian@163.com> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://patch.msgid.link/20260814082742.148403-2-xiaofengmian@163.com Signed-off-by: Paul Walmsley <pjw@kernel.org>
patch_map() always creates a temporary writable mapping via fixmap for kernel text addresses, even when CONFIG_STRICT_KERNEL_RWX is disabled and the kernel text is already mapped with _PAGE_WRITE. This is unnecessary overhead at best, and on minimal configurations it can cause page faults. Skip the fixmap path for kernel text when CONFIG_STRICT_KERNEL_RWX is not enabled, since the text pages are already writable in that case. The module text path is already gated on CONFIG_STRICT_MODULE_RWX and is kept unchanged. Reported-by: Klara Modin <klara@kasm.eu> Closes: https://lore.kernel.org/all/ant_8TaBbov_GS4i@soda.int.kasm.eu/ Reported-by: Lad Prabhakar <prabhakar.csengg@gmail.com> Closes: https://lore.kernel.org/all/CA+V-a8tQK8rih9SGGTyqrEBGpNkx4H0eX2YccCRrgkVAPr+EBg@mail.gmail.com/ Tested-by: Klara Modin <klarasmodin@gmail.com> Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Link: https://patch.msgid.link/20260814082742.148403-3-xiaofengmian@163.com Signed-off-by: Paul Walmsley <pjw@kernel.org>
This reverts commit 3033b2b. The reverted patch is userspace-visible behavior change, not a bug fix. The two variables here (pmm and pmlen) control two independent features: pmm is the _hardware_ pointer masking mode that applies while executing in userspace. pmlen is the shift amount that the _kernel_ uses when untagging addresses; PMLEN_0 means no untagging occurs, so the kernel does not accept tagged addresses in syscall arguments. It is valid (as documented and tested by the self test) to enable pointer masking without enabling the tagged address ABI. This separation is necessary to allow userspace to create an execution environment similar to what the kernel supports on arm64 by default, where TBI is enabled but the tagged address ABI is not. (On arm64, there is no equivalent to PR_PMLEN_MASK because TBI is always enabled.) Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Link: https://patch.msgid.link/20260820014551.1979772-1-samuel.holland@sifive.com Cc: stable@vger.kernel.org Fixes: 3033b2b ("riscv: Reset pmm when PR_TAGGED_ADDR_ENABLE is not set") Signed-off-by: Paul Walmsley <pjw@kernel.org>
Prefer the convenient string choice 'str_disabled_enabled()' helper over hardcoded strings in 'setup_global_riscv_enable()'. Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Link: https://patch.msgid.link/20260819160546.3219942-1-dmantipov@yandex.ru Signed-off-by: Paul Walmsley <pjw@kernel.org>
The vendor-extension handlers reached from hwprobe_one_pair() (hwprobe_isa_vendor_ext_thead_0() and friends) only OR the present bits into pair->value via VENDOR_EXTENSION_SUPPORTED() and clear their own missing bits; they assume the caller has already zeroed pair->value. That holds for hwprobe_get_values() (it zeroes each pair) and hwprobe_get_cpus() (it re-initializes its scratch pair per key), but not for complete_hwprobe_vdso_data(), which reuses a single pair across all keys without re-zeroing. A vendor key therefore inherits stale bits from the previously probed key, and the wrong value is cached in the vDSO all_cpu_hwprobe_values[] and handed to userspace on the fast patih. Zero pair->value once at the top of hwprobe_one_pair() so every handler starts from a clean value regardless of the caller, and drop the now redundant zeroing in the *_BLOCK_SIZE cases. hwprobe_isa_ext0() keeps its own zeroing because hwprobe_ext0_has() calls it directly, bypassing hwprobe_one_pair(). Fixes: a5ea53d ("riscv: hwprobe: Add thead vendor extension probing") Signed-off-by: Andy Chiu <tchiu@tenstorrent.com> Reviewed-by: Jesse Taube <jtaubepe@redhat.com> Link: https://patch.msgid.link/20260725001614.2578617-2-tchiu@tenstorrent.com Cc: stable@vger.kernel.org Signed-off-by: Paul Walmsley <pjw@kernel.org>
x86 did this in commit b0a848f ("x86/bugs: Make i386 use GENERIC_BUG_RELATIVE_POINTERS") powerpc did this in commit 1baa1f7 ("powerpc: Allow relative pointers in bug table entries") Similar as x86 and powerpc does, make RV32 use GENERIC_BUG_RELATIVE_POINTERS for "there is only one code path." and "less #ifdef is more better". Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Link: https://patch.msgid.link/20260221024255.3552-1-jszhang@kernel.org Signed-off-by: Paul Walmsley <pjw@kernel.org>
The RISC-V virtual memory layout documentation describes the 64-bit paging modes but leaves the Sv32 section as a TODO. Document the rv32_defconfig layout and clarify which boundaries depend on the configured size of struct page. Distinguish the maximum direct-map range from the portion backed by physical memory. Also explain why the 34-bit physical addresses encoded by Sv32 page table entries do not make all of that address space usable as RAM by the current RV32 kernel. Signed-off-by: Yu Jin <lambda.jinyu@gmail.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
RV32 defines TASK_SIZE as FIXADDR_START. Its value depends on VMEMMAP_SIZE, which in turn depends on the configured size of struct page. The fixed 0x9fc00000 value in the comment is therefore stale. Describe the macro relationship instead of replacing one configuration-specific address with another. Signed-off-by: Yu Jin <lambda.jinyu@gmail.com> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 1: "[RFC,1/2] docs: riscv: document the Sv32 virtual memory layout" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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Patch 2: "[RFC,2/2] riscv: mm: correct the stale RV32 TASK_SIZE comment" |
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PR for series 1153951 applied to workflow__riscv__fixes
Name: riscv: document the Sv32 virtual memory layout
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1153951
Version: 1