| Message ID | 20220201150545.1512822-16-guoren@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | riscv: compat: Add COMPAT mode support for rv64 | expand |
On Tue, Feb 1, 2022 at 11:07 PM <guoren@kernel.org> wrote: > > 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) Forgot __init, here > +{ > + 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 >
On Tue, Feb 01, 2022 at 11:05:39PM +0800, guoren@kernel.org wrote: > +bool compat_elf_check_arch(Elf32_Ehdr *hdr) > +{ > + if (compat_mode_support && (hdr->e_machine == EM_RISCV)) > + return true; > + else > + return false; > +} This can be simplified to: return compat_mode_support && hdr->e_machine == EM_RISCV; I'd also rename compat_mode_support to compat_mode_supported > + > +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"); > + } I don't think we need these printks here. Also this could be simplified to: compat_mode_supported = (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32;
On Wed, Feb 2, 2022 at 3:52 PM Christoph Hellwig <hch@lst.de> wrote: > > On Tue, Feb 01, 2022 at 11:05:39PM +0800, guoren@kernel.org wrote: > > +bool compat_elf_check_arch(Elf32_Ehdr *hdr) > > +{ > > + if (compat_mode_support && (hdr->e_machine == EM_RISCV)) > > + return true; > > + else > > + return false; > > +} > > This can be simplified to: > > return compat_mode_support && hdr->e_machine == EM_RISCV; Good point. > > I'd also rename compat_mode_support to compat_mode_supported Okay > > > + > > +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"); > > + } > > I don't think we need these printks here. Okay > > Also this could be simplified to: > > compat_mode_supported = (csr_read(CSR_STATUS) & SR_UXL) == SR_UXL_32; Okay
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) {