[PATCH V2 08/17] riscv: compat: Re-implement TASK_SIZE for COMPAT_32BIT
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STALE1731d
From: guoren@kernel.org
Date: 2021-12-28 14:41:05
Also in:
linux-mips, linux-riscv, linux-s390, linuxppc-dev, lkml, sparclinux
Subsystem:
extensible firmware interface (efi), risc-v architecture, the rest · Maintainers:
Ard Biesheuvel, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
Revision v2 of 6 in this series.
Revisions (6)
From: Guo Ren <redacted> Make TASK_SIZE from const to dynamic detect TIF_32BIT flag function. Refer to arm64 to implement DEFAULT_MAP_WINDOW_64 for efi-stub. Limit 32-bit compatible process in 0-2GB virtual address range (which is enough for real scenarios), because it could avoid address sign extend problem when 32-bit enter 64-bit and ease software design. The standard 32-bit TASK_SIZE is 0x9dc00000:FIXADDR_START, and compared to a compatible 32-bit, it increases 476MB for the application's virtual address. Signed-off-by: Guo Ren <redacted> Signed-off-by: Guo Ren <guoren@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> --- arch/riscv/include/asm/pgtable.h | 11 ++++++++++- arch/riscv/include/asm/processor.h | 6 ++++++ drivers/firmware/efi/libstub/efi-stub.c | 2 +- 3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index bf204e7c1f74..2dd5b8674380 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h@@ -663,7 +663,16 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, * Note that PGDIR_SIZE must evenly divide TASK_SIZE. */ #ifdef CONFIG_64BIT -#define TASK_SIZE (PGDIR_SIZE * PTRS_PER_PGD / 2) +#define TASK_SIZE_64 (PGDIR_SIZE * PTRS_PER_PGD / 2) + +#ifdef CONFIG_COMPAT +#define TASK_SIZE_32 (_AC(0x80000000, UL) - PAGE_SIZE) +#define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ + TASK_SIZE_32 : TASK_SIZE_64) +#else +#define TASK_SIZE TASK_SIZE_64 +#endif + #else #define TASK_SIZE FIXADDR_START #endif
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 0749924d9e55..8649436b8fcf 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h@@ -61,6 +61,12 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset, extern void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp); +#ifdef CONFIG_COMPAT +#define DEFAULT_MAP_WINDOW_64 TASK_SIZE_64 +#else +#define DEFAULT_MAP_WINDOW_64 TASK_SIZE +#endif + /* Free all resources held by a thread. */ static inline void release_thread(struct task_struct *dead_task) {
diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
index 26e69788f27a..4075fd19d219 100644
--- a/drivers/firmware/efi/libstub/efi-stub.c
+++ b/drivers/firmware/efi/libstub/efi-stub.c@@ -38,7 +38,7 @@ #define EFI_RT_VIRTUAL_BASE SZ_512M #define EFI_RT_VIRTUAL_SIZE SZ_512M -#ifdef CONFIG_ARM64 +#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV) # define EFI_RT_VIRTUAL_LIMIT DEFAULT_MAP_WINDOW_64 #else # define EFI_RT_VIRTUAL_LIMIT TASK_SIZE
--
2.25.1
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