From 8d7e8240e66cecc84a375aceb26942d02b291198 Mon Sep 17 00:00:00 2001 From: Chris Zankel Date: Tue, 12 Feb 2008 11:55:32 -0800 Subject: [XTENSA] Clean up elf-gregset. Remove additional registers from the ELF gregset structure that are only used by the kernel or are not required or invalid in user-space. The ar registers are always aligned to a windowbase value of 0, and the WB register is always assumed to be 0. Increase the size of the structure to 128 entries. This will provide enough space in future. Signed-off-by: Chris Zankel --- arch/xtensa/kernel/process.c | 63 +++++--------------------------------------- 1 file changed, 6 insertions(+), 57 deletions(-) (limited to 'arch/xtensa/kernel/process.c') diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index f53d7bd9dfb2..026138d641a4 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -194,51 +194,18 @@ unsigned long get_wchan(struct task_struct *p) void do_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs, struct task_struct *tsk) { - int i, n, wb_offset; - - elfregs->xchal_config_id0 = XCHAL_HW_CONFIGID0; - elfregs->xchal_config_id1 = XCHAL_HW_CONFIGID1; - - __asm__ __volatile__ ("rsr %0, 176\n" : "=a" (i)); - elfregs->cpux = i; - __asm__ __volatile__ ("rsr %0, 208\n" : "=a" (i)); - elfregs->cpuy = i; - /* Note: PS.EXCM is not set while user task is running; its * being set in regs->ps is for exception handling convenience. */ elfregs->pc = regs->pc; elfregs->ps = (regs->ps & ~(1 << PS_EXCM_BIT)); - elfregs->exccause = regs->exccause; - elfregs->excvaddr = regs->excvaddr; - elfregs->windowbase = regs->windowbase; - elfregs->windowstart = regs->windowstart; elfregs->lbeg = regs->lbeg; elfregs->lend = regs->lend; elfregs->lcount = regs->lcount; elfregs->sar = regs->sar; - elfregs->syscall = regs->syscall; - - /* Copy register file. - * The layout looks like this: - * - * | a0 ... a15 | Z ... Z | arX ... arY | - * current window unused saved frames - */ - - memset (elfregs->ar, 0, sizeof(elfregs->ar)); - - wb_offset = regs->windowbase * 4; - n = (regs->wmask&1)? 4 : (regs->wmask&2)? 8 : (regs->wmask&4)? 12 : 16; - - for (i = 0; i < n; i++) - elfregs->ar[(wb_offset + i) % XCHAL_NUM_AREGS] = regs->areg[i]; - n = (regs->wmask >> 4) * 4; - - for (i = XCHAL_NUM_AREGS - n; n > 0; i++, n--) - elfregs->ar[(wb_offset + i) % XCHAL_NUM_AREGS] = regs->areg[i]; + memcpy (elfregs->a, regs->areg, sizeof(elfregs->a)); } void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs) @@ -252,40 +219,22 @@ void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs) void do_restore_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs, struct task_struct *tsk) { - int i, n, wb_offset; + const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK; + unsigned long ps; /* Note: PS.EXCM is not set while user task is running; it * needs to be set in regs->ps is for exception handling convenience. */ + ps = (regs->ps & ~ps_mask) | (elfregs->ps & ps_mask) | (1<ps = ps; regs->pc = elfregs->pc; - regs->ps = (elfregs->ps | (1 << PS_EXCM_BIT)); - regs->exccause = elfregs->exccause; - regs->excvaddr = elfregs->excvaddr; - regs->windowbase = elfregs->windowbase; - regs->windowstart = elfregs->windowstart; regs->lbeg = elfregs->lbeg; regs->lend = elfregs->lend; regs->lcount = elfregs->lcount; regs->sar = elfregs->sar; - regs->syscall = elfregs->syscall; - - /* Clear everything. */ - - memset (regs->areg, 0, sizeof(regs->areg)); - - /* Copy regs from live window frame. */ - - wb_offset = regs->windowbase * 4; - n = (regs->wmask&1)? 4 : (regs->wmask&2)? 8 : (regs->wmask&4)? 12 : 16; - - for (i = 0; i < n; i++) - regs->areg[(wb_offset+i) % XCHAL_NUM_AREGS] = elfregs->ar[i]; - - n = (regs->wmask >> 4) * 4; - for (i = XCHAL_NUM_AREGS - n; n > 0; i++, n--) - regs->areg[(wb_offset+i) % XCHAL_NUM_AREGS] = elfregs->ar[i]; + memcpy (regs->areg, elfregs->a, sizeof(regs->areg)); } /* -- cgit v1.2.2 From c658eac628aa8df040dfe614556d95e6da3a9ffb Mon Sep 17 00:00:00 2001 From: Chris Zankel Date: Tue, 12 Feb 2008 13:17:07 -0800 Subject: [XTENSA] Add support for configurable registers and coprocessors The Xtensa architecture allows to define custom instructions and registers. Registers that are bound to a coprocessor are only accessible if the corresponding enable bit is set, which allows to implement a 'lazy' context switch mechanism. Other registers needs to be saved and restore at the time of the context switch or during interrupt handling. This patch adds support for these additional states: - save and restore registers that are used by the compiler upon interrupt entry and exit. - context switch additional registers unbound to any coprocessor - 'lazy' context switch of registers bound to a coprocessor - ptrace interface to provide access to additional registers - update configuration files in include/asm-xtensa/variant-fsf Signed-off-by: Chris Zankel --- arch/xtensa/kernel/process.c | 261 +++++++++++++++++-------------------------- 1 file changed, 102 insertions(+), 159 deletions(-) (limited to 'arch/xtensa/kernel/process.c') diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index 026138d641a4..9185597eb6a0 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -52,6 +52,55 @@ void (*pm_power_off)(void) = NULL; EXPORT_SYMBOL(pm_power_off); +#if XTENSA_HAVE_COPROCESSORS + +void coprocessor_release_all(struct thread_info *ti) +{ + unsigned long cpenable; + int i; + + /* Make sure we don't switch tasks during this operation. */ + + preempt_disable(); + + /* Walk through all cp owners and release it for the requested one. */ + + cpenable = ti->cpenable; + + for (i = 0; i < XCHAL_CP_MAX; i++) { + if (coprocessor_owner[i] == ti) { + coprocessor_owner[i] = 0; + cpenable &= ~(1 << i); + } + } + + ti->cpenable = cpenable; + coprocessor_clear_cpenable(); + + preempt_enable(); +} + +void coprocessor_flush_all(struct thread_info *ti) +{ + unsigned long cpenable; + int i; + + preempt_disable(); + + cpenable = ti->cpenable; + + for (i = 0; i < XCHAL_CP_MAX; i++) { + if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti) + coprocessor_flush(ti, i); + cpenable >>= 1; + } + + preempt_enable(); +} + +#endif + + /* * Powermanagement idle function, if any is provided by the platform. */ @@ -71,15 +120,36 @@ void cpu_idle(void) } /* - * Free current thread data structures etc.. + * This is called when the thread calls exit(). */ - void exit_thread(void) { +#if XTENSA_HAVE_COPROCESSORS + coprocessor_release_all(current_thread_info()); +#endif } +/* + * Flush thread state. This is called when a thread does an execve() + * Note that we flush coprocessor registers for the case execve fails. + */ void flush_thread(void) { +#if XTENSA_HAVE_COPROCESSORS + struct thread_info *ti = current_thread_info(); + coprocessor_flush_all(ti); + coprocessor_release_all(ti); +#endif +} + +/* + * This is called before the thread is copied. + */ +void prepare_to_copy(struct task_struct *tsk) +{ +#if XTENSA_HAVE_COPROCESSORS + coprocessor_flush_all(task_thread_info(tsk)); +#endif } /* @@ -107,6 +177,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, struct task_struct * p, struct pt_regs * regs) { struct pt_regs *childregs; + struct thread_info *ti; unsigned long tos; int user_mode = user_mode(regs); @@ -128,13 +199,14 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, p->set_child_tid = p->clear_child_tid = NULL; p->thread.ra = MAKE_RA_FOR_CALL((unsigned long)ret_from_fork, 0x1); p->thread.sp = (unsigned long)childregs; + if (user_mode(regs)) { int len = childregs->wmask & ~0xf; childregs->areg[1] = usp; memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4], ®s->areg[XCHAL_NUM_AREGS - len/4], len); - +// FIXME: we need to set THREADPTR in thread_info... if (clone_flags & CLONE_SETTLS) childregs->areg[2] = childregs->areg[6]; @@ -142,6 +214,12 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, /* In kernel space, we start a new thread with a new stack. */ childregs->wmask = 1; } + +#if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS) + ti = task_thread_info(p); + ti->cpenable = 0; +#endif + return 0; } @@ -179,10 +257,6 @@ unsigned long get_wchan(struct task_struct *p) } /* - * do_copy_regs() gathers information from 'struct pt_regs' and - * 'current->thread.areg[]' to fill in the xtensa_gregset_t - * structure. - * * xtensa_gregset_t and 'struct pt_regs' are vastly different formats * of processor registers. Besides different ordering, * xtensa_gregset_t contains non-live register information that @@ -191,9 +265,20 @@ unsigned long get_wchan(struct task_struct *p) * */ -void do_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs, - struct task_struct *tsk) +void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs) { + unsigned long wb, ws, wm; + int live, last; + + wb = regs->windowbase; + ws = regs->windowstart; + wm = regs->wmask; + ws = ((ws >> wb) | (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1); + + /* Don't leak any random bits. */ + + memset(elfregs, 0, sizeof (elfregs)); + /* Note: PS.EXCM is not set while user task is running; its * being set in regs->ps is for exception handling convenience. */ @@ -204,159 +289,18 @@ void do_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs, elfregs->lend = regs->lend; elfregs->lcount = regs->lcount; elfregs->sar = regs->sar; + elfregs->windowstart = ws; - memcpy (elfregs->a, regs->areg, sizeof(elfregs->a)); -} - -void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs) -{ - do_copy_regs ((xtensa_gregset_t *)elfregs, regs, current); -} - - -/* The inverse of do_copy_regs(). No error or sanity checking. */ - -void do_restore_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs, - struct task_struct *tsk) -{ - const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK; - unsigned long ps; - - /* Note: PS.EXCM is not set while user task is running; it - * needs to be set in regs->ps is for exception handling convenience. - */ - - ps = (regs->ps & ~ps_mask) | (elfregs->ps & ps_mask) | (1<ps = ps; - regs->pc = elfregs->pc; - regs->lbeg = elfregs->lbeg; - regs->lend = elfregs->lend; - regs->lcount = elfregs->lcount; - regs->sar = elfregs->sar; - - memcpy (regs->areg, elfregs->a, sizeof(regs->areg)); -} - -/* - * do_save_fpregs() gathers information from 'struct pt_regs' and - * 'current->thread' to fill in the elf_fpregset_t structure. - * - * Core files and ptrace use elf_fpregset_t. - */ - -void do_save_fpregs (elf_fpregset_t *fpregs, struct pt_regs *regs, - struct task_struct *tsk) -{ -#if XCHAL_HAVE_CP - - extern unsigned char _xtensa_reginfo_tables[]; - extern unsigned _xtensa_reginfo_table_size; - int i; - unsigned long flags; - - /* Before dumping coprocessor state from memory, - * ensure any live coprocessor contents for this - * task are first saved to memory: - */ - local_irq_save(flags); - - for (i = 0; i < XCHAL_CP_MAX; i++) { - if (tsk == coprocessor_info[i].owner) { - enable_coprocessor(i); - save_coprocessor_registers( - tsk->thread.cp_save+coprocessor_info[i].offset,i); - disable_coprocessor(i); - } - } - - local_irq_restore(flags); - - /* Now dump coprocessor & extra state: */ - memcpy((unsigned char*)fpregs, - _xtensa_reginfo_tables, _xtensa_reginfo_table_size); - memcpy((unsigned char*)fpregs + _xtensa_reginfo_table_size, - tsk->thread.cp_save, XTENSA_CP_EXTRA_SIZE); -#endif + live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16; + last = XCHAL_NUM_AREGS - (wm >> 4) * 4; + memcpy(elfregs->a, regs->areg, live * 4); + memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16); } -/* - * The inverse of do_save_fpregs(). - * Copies coprocessor and extra state from fpregs into regs and tsk->thread. - * Returns 0 on success, non-zero if layout doesn't match. - */ - -int do_restore_fpregs (elf_fpregset_t *fpregs, struct pt_regs *regs, - struct task_struct *tsk) +int dump_fpu(void) { -#if XCHAL_HAVE_CP - - extern unsigned char _xtensa_reginfo_tables[]; - extern unsigned _xtensa_reginfo_table_size; - int i; - unsigned long flags; - - /* Make sure save area layouts match. - * FIXME: in the future we could allow restoring from - * a different layout of the same registers, by comparing - * fpregs' table with _xtensa_reginfo_tables and matching - * entries and copying registers one at a time. - * Not too sure yet whether that's very useful. - */ - - if( memcmp((unsigned char*)fpregs, - _xtensa_reginfo_tables, _xtensa_reginfo_table_size) ) { - return -1; - } - - /* Before restoring coprocessor state from memory, - * ensure any live coprocessor contents for this - * task are first invalidated. - */ - - local_irq_save(flags); - - for (i = 0; i < XCHAL_CP_MAX; i++) { - if (tsk == coprocessor_info[i].owner) { - enable_coprocessor(i); - save_coprocessor_registers( - tsk->thread.cp_save+coprocessor_info[i].offset,i); - coprocessor_info[i].owner = 0; - disable_coprocessor(i); - } - } - - local_irq_restore(flags); - - /* Now restore coprocessor & extra state: */ - - memcpy(tsk->thread.cp_save, - (unsigned char*)fpregs + _xtensa_reginfo_table_size, - XTENSA_CP_EXTRA_SIZE); -#endif return 0; } -/* - * Fill in the CP structure for a core dump for a particular task. - */ - -int -dump_task_fpu(struct pt_regs *regs, struct task_struct *task, elf_fpregset_t *r) -{ - return 0; /* no coprocessors active on this processor */ -} - -/* - * Fill in the CP structure for a core dump. - * This includes any FPU coprocessor. - * Here, we dump all coprocessors, and other ("extra") custom state. - * - * This function is called by elf_core_dump() in fs/binfmt_elf.c - * (in which case 'regs' comes from calls to do_coredump, see signals.c). - */ -int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) -{ - return dump_task_fpu(regs, current, r); -} asmlinkage long xtensa_clone(unsigned long clone_flags, unsigned long newsp, @@ -370,8 +314,8 @@ long xtensa_clone(unsigned long clone_flags, unsigned long newsp, } /* - * * xtensa_execve() executes a new program. - * */ + * xtensa_execve() executes a new program. + */ asmlinkage long xtensa_execve(char __user *name, char __user * __user *argv, @@ -386,7 +330,6 @@ long xtensa_execve(char __user *name, char __user * __user *argv, error = PTR_ERR(filename); if (IS_ERR(filename)) goto out; - // FIXME: release coprocessor?? error = do_execve(filename, argv, envp, regs); if (error == 0) { task_lock(current); -- cgit v1.2.2