diff mbox series

[04/13] riscv: compat: Re-implement TASK_SIZE for COMPAT_32BIT

Message ID 20211221163532.2636028-5-guoren@kernel.org (mailing list archive)
State New, archived
Headers show
Series riscv: compat: Add COMPAT mode support for rv64 | expand

Commit Message

Guo Ren Dec. 21, 2021, 4:35 p.m. UTC 
From: Guo Ren <guoren@linux.alibaba.com>

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 <guoren@linux.alibaba.com>
---
 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 mbox series

Patch

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