On 2024-08-27 00:36, Charlie Jenkins wrote:
The hint address should not forcefully restrict the addresses returned by mmap as this causes mmap to report ENOMEM when there is memory still available.
Signed-off-by: Charlie Jenkins charlie@rivosinc.com Fixes: b5b4287accd7 ("riscv: mm: Use hint address in mmap if available") Fixes: add2cc6b6515 ("RISC-V: mm: Restrict address space for sv39,sv48,sv57") Closes: https://lore.kernel.org/linux-kernel/ZbxTNjQPFKBatMq+@ghost/T/#mccb1890466bf...
arch/riscv/include/asm/processor.h | 26 ++------------------------ 1 file changed, 2 insertions(+), 24 deletions(-)
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 8702b8721a27..efa1b3519b23 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -14,36 +14,14 @@ #include <asm/ptrace.h> -/*
- addr is a hint to the maximum userspace address that mmap should provide, so
- this macro needs to return the largest address space available so that
- mmap_end < addr, being mmap_end the top of that address space.
- See Documentation/arch/riscv/vm-layout.rst for more details.
- */ #define arch_get_mmap_end(addr, len, flags) \ ({ \
- unsigned long mmap_end; \
- typeof(addr) _addr = (addr); \
- if ((_addr) == 0 || is_compat_task() || \
((_addr + len) > BIT(VA_BITS - 1))) \mmap_end = STACK_TOP_MAX; \- else \
mmap_end = (_addr + len); \- mmap_end; \
- STACK_TOP_MAX; \ })
#define arch_get_mmap_base(addr, base) \ ({ \
- unsigned long mmap_base; \
- typeof(addr) _addr = (addr); \
- typeof(base) _base = (base); \
- unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base); \
- if ((_addr) == 0 || is_compat_task() || \
((_addr + len) > BIT(VA_BITS - 1))) \mmap_base = (_base); \- else \
mmap_base = (_addr + len) - rnd_gap; \- mmap_base; \
- base; \ })
#ifdef CONFIG_64BIT
I tested this patch on 6.10.2 kernel and could confirm that it fixes the crash of chromium. But I think I prefer Yangyu Chen's approach because that would avoid breaking some applications on sv57.
Tested-by: Levi Zim rsworktech@outlook.com # Chromium, sv39