From: guoren@kernel.org
To: guoren@kernel.org, palmer@dabbelt.com, arnd@arndb.de,
anup@brainfault.org, gregkh@linuxfoundation.org,
liush@allwinnertech.com, wefu@redhat.com, drew@beagleboard.org,
wangjunqiang@iscas.ac.cn, hch@lst.de, hch@infradead.org
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-csky@vger.kernel.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
inux-parisc@vger.kernel.org, linux-mips@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, x86@kernel.org,
Guo Ren <guoren@linux.alibaba.com>
Subject: [PATCH V3 09/17] riscv: compat: syscall: Add entry.S implementation
Date: Thu, 20 Jan 2022 15:39:02 +0800 [thread overview]
Message-ID: <20220120073911.99857-10-guoren@kernel.org> (raw)
From: Guo Ren <guoren@linux.alibaba.com>
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: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
---
arch/riscv/include/asm/csr.h | 7 +++++++
arch/riscv/kernel/entry.S | 18 ++++++++++++++++--
2 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 5046f431645c..7dac12366833 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -36,6 +36,13 @@
#define SR_SD _AC(0x8000000000000000, UL) /* FS/XS dirty */
#endif
+#ifdef CONFIG_COMPAT
+#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)
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index ed29e9c8f660..1951743f09b3 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -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:
--
2.25.1
reply other threads:[~2022-01-20 7:41 UTC|newest]
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