diff options
| author | Guo Ren <guoren@linux.alibaba.com> | 2022-04-05 15:13:09 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2022-04-26 13:36:47 -0700 |
| commit | f4b395e6f1a588ed6c9a30474e58cf6b27b65783 (patch) | |
| tree | a629aefc95eb698e8e479698acb9fdb90f028fe0 /arch/riscv/kernel | |
| parent | 87309e1082481bb78a9fbea6ed6784d979ff93c9 (diff) | |
riscv: compat: Add hw capability check for elf
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
Add CLASS to enhance (compat_)elf_check_arch to distinguish
32BIT/64BIT elf.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-16-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/kernel')
| -rw-r--r-- | arch/riscv/kernel/process.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c index b4421c16198c..1c7be865ab31 100644 --- a/arch/riscv/kernel/process.c +++ b/arch/riscv/kernel/process.c @@ -84,6 +84,34 @@ void show_regs(struct pt_regs *regs) dump_backtrace(regs, NULL, KERN_DEFAULT); } +#ifdef CONFIG_COMPAT +static bool compat_mode_supported __read_mostly; + +bool compat_elf_check_arch(Elf32_Ehdr *hdr) +{ + return compat_mode_supported && + hdr->e_machine == EM_RISCV && + hdr->e_ident[EI_CLASS] == ELFCLASS32; +} + +static int __init compat_mode_detect(void) +{ + unsigned long tmp = csr_read(CSR_STATUS); + + csr_write(CSR_STATUS, (tmp & ~SR_UXL) | SR_UXL_32); + compat_mode_supported = + (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32; + + csr_write(CSR_STATUS, tmp); + + pr_info("riscv: ELF compat mode %s", + compat_mode_supported ? "supported" : "failed"); + + return 0; +} +early_initcall(compat_mode_detect); +#endif + void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) { |