Unverified Commit 728e7ea2 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

Merge patch series "riscv: Introduce compat-mode helpers & improve arch_get_mmap_end()" 

Leonardo Bras <leobras@redhat.com> says:

I just saw the opportunity of optimizing the helper is_compat_task() by
introducing a compile-time test, and it made possible to remove some
 #ifdef's without any loss of performance.

I also saw the possibility of removing the direct check of task flags from
general code, and concentrated it in asm/compat.h by creating a few more
helpers, which in the end helped optimize code.

arch_get_mmap_end() just got a simple improvement and some extra docs.

* b4-shazam-merge:
  riscv: Introduce set_compat_task() in asm/compat.h
  riscv: Introduce is_compat_thread() into compat.h
  riscv: add compile-time test into is_compat_task()
  riscv: Replace direct thread flag check with is_compat_task()
  riscv: Improve arch_get_mmap_end() macro

Link: https://lore.kernel.org/r/20240103160024.70305-2-leobras@redhat.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parents 700c2d9b 2a8986fc

arch/riscv/include/asm/compat.h

+19 −0
Original line number Diff line number Diff line
@@ -14,9 +14,28 @@ 


static inline int is_compat_task(void)

{

	if (!IS_ENABLED(CONFIG_COMPAT))

		return 0;



	return test_thread_flag(TIF_32BIT);

}



static inline int is_compat_thread(struct thread_info *thread)

{

	if (!IS_ENABLED(CONFIG_COMPAT))

		return 0;



	return test_ti_thread_flag(thread, TIF_32BIT);

}



static inline void set_compat_task(bool is_compat)

{

	if (is_compat)

		set_thread_flag(TIF_32BIT);

	else

		clear_thread_flag(TIF_32BIT);

}



struct compat_user_regs_struct {

	compat_ulong_t pc;

	compat_ulong_t ra;

arch/riscv/include/asm/elf.h

+2 −9
Original line number Diff line number Diff line
@@ -53,13 +53,9 @@ extern bool compat_elf_check_arch(Elf32_Ehdr *hdr); 
#define ELF_ET_DYN_BASE		((DEFAULT_MAP_WINDOW / 3) * 2)



#ifdef CONFIG_64BIT

#ifdef CONFIG_COMPAT

#define STACK_RND_MASK		(test_thread_flag(TIF_32BIT) ? \

#define STACK_RND_MASK		(is_compat_task() ? \

				 0x7ff >> (PAGE_SHIFT - 12) : \

				 0x3ffff >> (PAGE_SHIFT - 12))

#else

#define STACK_RND_MASK		(0x3ffff >> (PAGE_SHIFT - 12))

#endif

#endif



/*
@@ -139,10 +135,7 @@ do { \ 
#ifdef CONFIG_COMPAT



#define SET_PERSONALITY(ex)					\

do {    if ((ex).e_ident[EI_CLASS] == ELFCLASS32)		\

		set_thread_flag(TIF_32BIT);			\

	else							\

		clear_thread_flag(TIF_32BIT);			\

do {	set_compat_task((ex).e_ident[EI_CLASS] == ELFCLASS32);	\

	if (personality(current->personality) != PER_LINUX32)	\

		set_personality(PER_LINUX |			\

			(current->personality & (~PER_MASK)));	\

arch/riscv/include/asm/pgtable.h

+2 −8
Original line number Diff line number Diff line
@@ -127,16 +127,10 @@ 
#define VA_USER_SV48 (UL(1) << (VA_BITS_SV48 - 1))

#define VA_USER_SV57 (UL(1) << (VA_BITS_SV57 - 1))



#ifdef CONFIG_COMPAT

#define MMAP_VA_BITS_64 ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)

#define MMAP_MIN_VA_BITS_64 (VA_BITS_SV39)

#define MMAP_VA_BITS (is_compat_task() ? VA_BITS_SV32 : MMAP_VA_BITS_64)

#define MMAP_MIN_VA_BITS (is_compat_task() ? VA_BITS_SV32 : MMAP_MIN_VA_BITS_64)

#else

#define MMAP_VA_BITS ((VA_BITS >= VA_BITS_SV48) ? VA_BITS_SV48 : VA_BITS)

#define MMAP_MIN_VA_BITS (VA_BITS_SV39)

#endif /* CONFIG_COMPAT */



#else

#include <asm/pgtable-32.h>

#endif /* CONFIG_64BIT */
@@ -877,8 +871,8 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) 
#define TASK_SIZE_MIN	(PGDIR_SIZE_L3 * PTRS_PER_PGD / 2)



#ifdef CONFIG_COMPAT

#define TASK_SIZE_32	(_AC(0x80000000, UL))

#define TASK_SIZE	(test_thread_flag(TIF_32BIT) ? \

#define TASK_SIZE_32	(_AC(0x80000000, UL) - PAGE_SIZE)

#define TASK_SIZE	(is_compat_task() ? \

			 TASK_SIZE_32 : TASK_SIZE_64)

#else

#define TASK_SIZE	TASK_SIZE_64

arch/riscv/include/asm/processor.h

+8 −4
Original line number Diff line number Diff line
@@ -14,12 +14,17 @@ 


#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_ENABLED(CONFIG_COMPAT) && is_compat_task()) ||	\

	if ((_addr) == 0 || is_compat_task() ||			\

	    ((_addr + len) > BIT(VA_BITS - 1)))			\

		mmap_end = STACK_TOP_MAX;			\

	else							\
@@ -33,8 +38,7 @@ 
	typeof(addr) _addr = (addr);				\

	typeof(base) _base = (base);				\

	unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base);	\

	if ((_addr) == 0 ||					\

	    (IS_ENABLED(CONFIG_COMPAT) && is_compat_task()) ||	\

	if ((_addr) == 0 || is_compat_task() || 		\

	    ((_addr + len) > BIT(VA_BITS - 1)))			\

		mmap_base = (_base);				\

	else							\

arch/riscv/kernel/ptrace.c

+3 −3
Original line number Diff line number Diff line
@@ -377,14 +377,14 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, 


	return ret;

}

#else

static const struct user_regset_view compat_riscv_user_native_view = {};

#endif /* CONFIG_COMPAT */



const struct user_regset_view *task_user_regset_view(struct task_struct *task)

{

#ifdef CONFIG_COMPAT

	if (test_tsk_thread_flag(task, TIF_32BIT))

	if (is_compat_thread(&task->thread_info))

		return &compat_riscv_user_native_view;

	else

#endif

		return &riscv_user_native_view;

}