| Message ID | 20220308072005.307955-8-richard.henderson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | target/nios2: Shadow register set, EIC and VIC | expand |
On Tue, 8 Mar 2022 at 07:20, Richard Henderson <richard.henderson@linaro.org> wrote: > > The only thing this struct is used for is passing startup values > from elfload.c to the cpu. We do not need all registers to be > represented, we do not need the kernel internal stack slots. > > The userland argc, argv, and envp values are passed on > the stack, so only SP and PC need updating. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > linux-user/nios2/target_syscall.h | 25 ++----------------------- > linux-user/elfload.c | 3 +-- > linux-user/nios2/cpu_loop.c | 24 +----------------------- > 3 files changed, 4 insertions(+), 48 deletions(-) Well, I guess we're not using it for anything else currently, but if you do this then it's not the target arch's pt_regs struct any more. And all our other target archs seem to define the struct to follow the kernel definition even if we don't happen to use it all. -- PMM
On 3/8/22 00:00, Peter Maydell wrote: > On Tue, 8 Mar 2022 at 07:20, Richard Henderson > <richard.henderson@linaro.org> wrote: >> >> The only thing this struct is used for is passing startup values >> from elfload.c to the cpu. We do not need all registers to be >> represented, we do not need the kernel internal stack slots. >> >> The userland argc, argv, and envp values are passed on >> the stack, so only SP and PC need updating. >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> --- >> linux-user/nios2/target_syscall.h | 25 ++----------------------- >> linux-user/elfload.c | 3 +-- >> linux-user/nios2/cpu_loop.c | 24 +----------------------- >> 3 files changed, 4 insertions(+), 48 deletions(-) > > Well, I guess we're not using it for anything else currently, > but if you do this then it's not the target arch's pt_regs > struct any more. And all our other target archs seem to define > the struct to follow the kernel definition even if we don't > happen to use it all. Yes, something I've meant to clean up for ages. My real goal here was removing the reference to estatus, which then does not need to be converted to a different form in the coming patches. (Assigning to estatus is unusable in user-mode, because rdctl and eret are supervisor insns. This code appears to be mirroring the kernel code in which it is trying to get the right bits ready for the context switch to user-mode. For qemu, we've done that for user-only during reset, and with proper symbolic constants, so no need to do it again here.) I could just remove the two mentions of estatus in init_thread and copy_regs, if that seems better. Leave the target_pt_regs cleanup to a larger patch set touching them all. r~
diff --git a/linux-user/nios2/target_syscall.h b/linux-user/nios2/target_syscall.h index 561b28d281..0999ce25fd 100644 --- a/linux-user/nios2/target_syscall.h +++ b/linux-user/nios2/target_syscall.h @@ -5,29 +5,8 @@ #define UNAME_MINIMUM_RELEASE "3.19.0" struct target_pt_regs { - unsigned long r8; /* r8-r15 Caller-saved GP registers */ - unsigned long r9; - unsigned long r10; - unsigned long r11; - unsigned long r12; - unsigned long r13; - unsigned long r14; - unsigned long r15; - unsigned long r1; /* Assembler temporary */ - unsigned long r2; /* Retval LS 32bits */ - unsigned long r3; /* Retval MS 32bits */ - unsigned long r4; /* r4-r7 Register arguments */ - unsigned long r5; - unsigned long r6; - unsigned long r7; - unsigned long orig_r2; /* Copy of r2 ?? */ - unsigned long ra; /* Return address */ - unsigned long fp; /* Frame pointer */ - unsigned long sp; /* Stack pointer */ - unsigned long gp; /* Global pointer */ - unsigned long estatus; - unsigned long ea; /* Exception return address (pc) */ - unsigned long orig_r7; + target_ulong sp; + target_ulong pc; }; #define TARGET_MCL_CURRENT 1 diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 23ff9659a5..cb14c5f786 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1094,9 +1094,8 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUMBState *env static void init_thread(struct target_pt_regs *regs, struct image_info *infop) { - regs->ea = infop->entry; + regs->pc = infop->entry; regs->sp = infop->start_stack; - regs->estatus = 0x3; } #define LO_COMMPAGE TARGET_PAGE_SIZE diff --git a/linux-user/nios2/cpu_loop.c b/linux-user/nios2/cpu_loop.c index 7b20c024db..37e1dfecfd 100644 --- a/linux-user/nios2/cpu_loop.c +++ b/linux-user/nios2/cpu_loop.c @@ -132,28 +132,6 @@ void cpu_loop(CPUNios2State *env) void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) { - env->regs[0] = 0; - env->regs[1] = regs->r1; - env->regs[2] = regs->r2; - env->regs[3] = regs->r3; - env->regs[4] = regs->r4; - env->regs[5] = regs->r5; - env->regs[6] = regs->r6; - env->regs[7] = regs->r7; - env->regs[8] = regs->r8; - env->regs[9] = regs->r9; - env->regs[10] = regs->r10; - env->regs[11] = regs->r11; - env->regs[12] = regs->r12; - env->regs[13] = regs->r13; - env->regs[14] = regs->r14; - env->regs[15] = regs->r15; - /* TODO: unsigned long orig_r2; */ - env->regs[R_RA] = regs->ra; - env->regs[R_FP] = regs->fp; env->regs[R_SP] = regs->sp; - env->regs[R_GP] = regs->gp; - env->regs[CR_ESTATUS] = regs->estatus; - env->pc = regs->ea; - /* TODO: unsigned long orig_r7; */ + env->pc = regs->pc; }
The only thing this struct is used for is passing startup values from elfload.c to the cpu. We do not need all registers to be represented, we do not need the kernel internal stack slots. The userland argc, argv, and envp values are passed on the stack, so only SP and PC need updating. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- linux-user/nios2/target_syscall.h | 25 ++----------------------- linux-user/elfload.c | 3 +-- linux-user/nios2/cpu_loop.c | 24 +----------------------- 3 files changed, 4 insertions(+), 48 deletions(-)