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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
Cc: linux-arch@vger.kernel.org, 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, linux-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 V5 15/21] riscv: compat: Add hw capability check for elf
Date: Tue,  1 Feb 2022 23:05:39 +0800	[thread overview]
Message-ID: <20220201150545.1512822-16-guoren@kernel.org> (raw)
In-Reply-To: <20220201150545.1512822-1-guoren@kernel.org>

From: Guo Ren <guoren@linux.alibaba.com>

Detect hardware COMPAT (32bit U-mode) capability in rv64. If not
support COMPAT mode in hw, compat_elf_check_arch would return
false by compat_binfmt_elf.c

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
---
 arch/riscv/include/asm/elf.h |  3 ++-
 arch/riscv/kernel/process.c  | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index aee40040917b..3a4293dc7229 100644
--- a/arch/riscv/include/asm/elf.h
+++ b/arch/riscv/include/asm/elf.h
@@ -40,7 +40,8 @@
  * elf64_hdr e_machine's offset are different. The checker is
  * a little bit simple compare to other architectures.
  */
-#define compat_elf_check_arch(x) ((x)->e_machine == EM_RISCV)
+extern bool compat_elf_check_arch(Elf32_Ehdr *hdr);
+#define compat_elf_check_arch	compat_elf_check_arch
 
 #define CORE_DUMP_USE_REGSET
 #define ELF_EXEC_PAGESIZE	(PAGE_SIZE)
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 1a666ad299b4..758847cba391 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -83,6 +83,38 @@ void show_regs(struct pt_regs *regs)
 		dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
+#ifdef CONFIG_COMPAT
+static bool compat_mode_support __read_mostly;
+
+bool compat_elf_check_arch(Elf32_Ehdr *hdr)
+{
+	if (compat_mode_support && (hdr->e_machine == EM_RISCV))
+		return true;
+	else
+		return false;
+}
+
+static int compat_mode_detect(void)
+{
+	unsigned long tmp = csr_read(CSR_STATUS);
+
+	csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32);
+
+	if ((csr_read(CSR_STATUS) & SR_UXL) != SR_UXL_32) {
+		pr_info("riscv: 32bit compat mode detect failed\n");
+		compat_mode_support = false;
+	} else {
+		compat_mode_support = true;
+		pr_info("riscv: 32bit compat mode detected\n");
+	}
+
+	csr_write(CSR_STATUS, tmp);
+
+	return 0;
+}
+arch_initcall(compat_mode_detect);
+#endif
+
 void start_thread(struct pt_regs *regs, unsigned long pc,
 	unsigned long sp)
 {
-- 
2.25.1


  parent reply	other threads:[~2022-02-01 15:07 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-01 15:05 [PATCH V5 00/21] riscv: compat: Add COMPAT mode support for rv64 guoren
2022-02-01 15:05 ` [PATCH V5 01/21] uapi: simplify __ARCH_FLOCK{,64}_PAD a little guoren
2022-02-01 15:05 ` [PATCH V5 02/21] uapi: always define F_GETLK64/F_SETLK64/F_SETLKW64 in fcntl.h guoren
2022-02-01 15:05 ` [PATCH V5 03/21] compat: consolidate the compat_flock{,64} definition guoren
2022-02-01 15:05 ` [PATCH V5 04/21] kconfig: Add SYSVIPC_COMPAT for all architectures guoren
2022-02-01 15:05 ` [PATCH V5 05/21] fs: stat: compat: Add __ARCH_WANT_COMPAT_STAT guoren
2022-02-01 15:05 ` [PATCH V5 06/21] asm-generic: compat: Cleanup duplicate definitions guoren
2022-02-02  7:48   ` Christoph Hellwig
2022-02-01 15:05 ` [PATCH V5 07/21] syscalls: compat: Fix the missing part for __SYSCALL_COMPAT guoren
2022-02-01 15:05 ` [PATCH V5 08/21] riscv: Fixup difference with defconfig guoren
2022-02-01 15:05 ` [PATCH V5 09/21] riscv: compat: Add basic compat data type implementation guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-23  8:54     ` Guo Ren
2022-02-01 15:05 ` [PATCH V5 10/21] riscv: compat: Re-implement TASK_SIZE for COMPAT_32BIT guoren
2022-02-01 15:05 ` [PATCH V5 11/21] riscv: compat: syscall: Add compat_sys_call_table implementation guoren
2022-02-01 15:05 ` [PATCH V5 12/21] riscv: compat: syscall: Add entry.S implementation guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-01 15:05 ` [PATCH V5 13/21] riscv: compat: process: Add UXL_32 support in start_thread guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-23  9:21     ` Guo Ren
2022-02-01 15:05 ` [PATCH V5 14/21] riscv: compat: Add elf.h implementation guoren
2022-02-01 15:05 ` guoren [this message]
2022-02-02  2:02   ` [PATCH V5 15/21] riscv: compat: Add hw capability check for elf Guo Ren
2022-02-02  7:51   ` Christoph Hellwig
2022-02-03  2:44     ` Guo Ren
2022-02-01 15:05 ` [PATCH V5 16/21] riscv: compat: vdso: Add rv32 VDSO base code implementation guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-23  9:55     ` Guo Ren
2022-02-01 15:05 ` [PATCH V5 17/21] riscv: compat: vdso: Add setup additional pages implementation guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-23 11:49     ` Guo Ren
2022-02-24  1:36     ` Guo Ren
2022-02-23 12:12   ` Rolf Eike Beer
2022-02-23 12:42     ` Guo Ren
2022-02-01 15:05 ` [PATCH V5 18/21] riscv: compat: signal: Add rt_frame implementation guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-01 15:05 ` [PATCH V5 19/21] riscv: compat: ptrace: Add compat_arch_ptrace implement guoren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-01 15:05 ` [PATCH V5 20/21] riscv: compat: Add COMPAT Kbuild skeletal support guoren
2022-02-01 15:05 ` [PATCH V5 21/21] KVM: compat: riscv: Prevent KVM_COMPAT from being selected guoren
2022-02-01 15:44   ` Anup Patel
2022-02-01 16:00     ` Paolo Bonzini
2022-02-01 16:11       ` Anup Patel
2022-02-01 16:16         ` Guo Ren
2022-02-23  1:42   ` Palmer Dabbelt
2022-02-08  7:43 ` [PATCH V5 00/21] riscv: compat: Add COMPAT mode support for rv64 Guo Ren
2022-02-23  1:43 ` Palmer Dabbelt
2022-02-23 10:59   ` Arnd Bergmann

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