Unverified Commit dfb0bfa7 authored by Guo Ren's avatar Guo Ren Committed by Palmer Dabbelt
Browse files

riscv: compat: syscall: Add entry.S implementation 



Implement the entry of compat_sys_call_table[] in asm. Ref to
riscv-privileged spec 4.1.1 Supervisor Status Register (sstatus):

 BIT[32:33] = UXL[1:0]:
 - 1:32
 - 2:64
 - 3:128

Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
Signed-off-by: default avatarGuo Ren <guoren@kernel.org>
Reviewed-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Tested-by: default avatarHeiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-13-guoren@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 59c10c52

arch/riscv/include/asm/csr.h

+7 −0
Original line number Diff line number Diff line
@@ -36,6 +36,13 @@ 
#define SR_SD		_AC(0x8000000000000000, UL) /* FS/XS dirty */

#endif



#ifdef CONFIG_64BIT

#define SR_UXL		_AC(0x300000000, UL) /* XLEN mask for U-mode */

#define SR_UXL_32	_AC(0x100000000, UL) /* XLEN = 32 for U-mode */

#define SR_UXL_64	_AC(0x200000000, UL) /* XLEN = 64 for U-mode */

#define SR_UXL_SHIFT	32

#endif



/* SATP flags */

#ifndef CONFIG_64BIT

#define SATP_PPN	_AC(0x003FFFFF, UL)

arch/riscv/kernel/entry.S

+16 −2
Original line number Diff line number Diff line
@@ -207,13 +207,27 @@ check_syscall_nr: 
	 * Syscall number held in a7.

	 * If syscall number is above allowed value, redirect to ni_syscall.

	 */

	bgeu a7, t0, 1f

	bgeu a7, t0, 3f

#ifdef CONFIG_COMPAT

	REG_L s0, PT_STATUS(sp)

	srli s0, s0, SR_UXL_SHIFT

	andi s0, s0, (SR_UXL >> SR_UXL_SHIFT)

	li t0, (SR_UXL_32 >> SR_UXL_SHIFT)

	sub t0, s0, t0

	bnez t0, 1f



	/* Call compat_syscall */

	la s0, compat_sys_call_table

	j 2f

1:

#endif

	/* Call syscall */

	la s0, sys_call_table

2:

	slli t0, a7, RISCV_LGPTR

	add s0, s0, t0

	REG_L s0, 0(s0)

1:

3:

	jalr s0



ret_from_syscall: