From 2f72d4f6a29cf84c40fc05c76020b347b4774393 Mon Sep 17 00:00:00 2001 From: Chris Zankel Date: Tue, 23 Oct 2012 20:17:05 -0700 Subject: [PATCH 1/6] xtensa: allow multi-inclusion for uapi/unistd.h Xtensa implements a method that allows to generate a arbitrary output for each system call by defining the __SYSCALL(number, function, num_args). This usually requires to include uapi/unistd.h twice. Instead of removing the guard agains multiple inclusion entirely, allow to include unistd.h again only if __SYSCALL is defined. Note that __SYSCALL gets always undefined at the end of the file. Signed-off-by: Chris Zankel --- arch/xtensa/include/asm/unistd.h | 14 ++++---------- arch/xtensa/include/uapi/asm/unistd.h | 14 +++----------- arch/xtensa/kernel/syscall.c | 7 +++---- 3 files changed, 10 insertions(+), 25 deletions(-) diff --git a/arch/xtensa/include/asm/unistd.h b/arch/xtensa/include/asm/unistd.h index 9ef1c31d2c83..d9fa52dbfba0 100644 --- a/arch/xtensa/include/asm/unistd.h +++ b/arch/xtensa/include/asm/unistd.h @@ -1,16 +1,8 @@ -/* - * include/asm-xtensa/unistd.h - * - * This file is subject to the terms and conditions of the GNU General Public - * License. See the file "COPYING" in the main directory of this archive - * for more details. - * - * Copyright (C) 2001 - 2005 Tensilica Inc. - */ +#ifndef _XTENSA_UNISTD_H +#define _XTENSA_UNISTD_H #include - /* * "Conditional" syscalls * @@ -37,3 +29,5 @@ #define __IGNORE_mmap /* use mmap2 */ #define __IGNORE_vfork /* use clone */ #define __IGNORE_fadvise64 /* use fadvise64_64 */ + +#endif /* _XTENSA_UNISTD_H */ diff --git a/arch/xtensa/include/uapi/asm/unistd.h b/arch/xtensa/include/uapi/asm/unistd.h index 479abaea5aae..1fd157f31211 100644 --- a/arch/xtensa/include/uapi/asm/unistd.h +++ b/arch/xtensa/include/uapi/asm/unistd.h @@ -1,14 +1,4 @@ -/* - * include/asm-xtensa/unistd.h - * - * This file is subject to the terms and conditions of the GNU General Public - * License. See the file "COPYING" in the main directory of this archive - * for more details. - * - * Copyright (C) 2001 - 2012 Tensilica Inc. - */ - -#ifndef _UAPI_XTENSA_UNISTD_H +#if !defined(_UAPI_XTENSA_UNISTD_H) || defined(__SYSCALL) #define _UAPI_XTENSA_UNISTD_H #ifndef __SYSCALL @@ -759,4 +749,6 @@ __SYSCALL(331, sys_kcmp, 5) #define SYS_XTENSA_COUNT 5 /* count */ +#undef __SYSCALL + #endif /* _UAPI_XTENSA_UNISTD_H */ diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c index a5c01e74d5d5..5702065f472a 100644 --- a/arch/xtensa/kernel/syscall.c +++ b/arch/xtensa/kernel/syscall.c @@ -32,10 +32,8 @@ typedef void (*syscall_t)(void); syscall_t sys_call_table[__NR_syscall_count] /* FIXME __cacheline_aligned */= { [0 ... __NR_syscall_count - 1] = (syscall_t)&sys_ni_syscall, -#undef __SYSCALL #define __SYSCALL(nr,symbol,nargs) [ nr ] = (syscall_t)symbol, -#undef __KERNEL_SYSCALLS__ -#include +#include }; asmlinkage long xtensa_shmat(int shmid, char __user *shmaddr, int shmflg) @@ -49,7 +47,8 @@ asmlinkage long xtensa_shmat(int shmid, char __user *shmaddr, int shmflg) return (long)ret; } -asmlinkage long xtensa_fadvise64_64(int fd, int advice, unsigned long long offset, unsigned long long len) +asmlinkage long xtensa_fadvise64_64(int fd, int advice, + unsigned long long offset, unsigned long long len) { return sys_fadvise64_64(fd, offset, len, advice); } From cddfcbcd05851a3b720055d40fc61c63ea1c2bd1 Mon Sep 17 00:00:00 2001 From: Chris Zankel Date: Tue, 23 Oct 2012 20:25:37 -0700 Subject: [PATCH 2/6] xtensa: use physical addresses for bus addresses Define virt_to_bus and bus_to_virt as virt_to_phys, and phys_to_virt, respectively. Signed-off-by: Chris Zankel --- arch/xtensa/include/asm/io.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/xtensa/include/asm/io.h b/arch/xtensa/include/asm/io.h index e6be5b9091c2..700c2e6f2d25 100644 --- a/arch/xtensa/include/asm/io.h +++ b/arch/xtensa/include/asm/io.h @@ -62,6 +62,10 @@ static inline void __iomem *ioremap(unsigned long offset, unsigned long size) static inline void iounmap(volatile void __iomem *addr) { } + +#define virt_to_bus virt_to_phys +#define bus_to_virt phys_to_virt + #endif /* CONFIG_MMU */ /* From 6ebe7da25b7879194fdb5c43ea67b383dd9014d6 Mon Sep 17 00:00:00 2001 From: Chris Zankel Date: Wed, 24 Oct 2012 13:15:21 -0700 Subject: [PATCH 3/6] xtensa: reset windowbase/windowstart when cloning the VM When we copy a user thread with CLONE_VM, we also have to reset windowbase and windowstart to start a pristine stack frame. Otherwise, overflows can happen using the address 0 as the stack pointer. Also add a special case for vfork, which continues on the parent stack until it calls execve. Because this could be a call8, we need to spill the stack pointer of the previus frame (if still 'live' in the register file). Signed-off-by: Chris Zankel --- arch/xtensa/kernel/process.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index 1908f6642d31..341c151af919 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -220,8 +220,32 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, if (user_mode(regs)) { childregs->areg[1] = usp; + + /* When sharing memory with the parent thread, the child + usually starts on a pristine stack, so we have to reset + windowbase, windowstart and wmask. + (Note that such a new thread is required to always create + an initial call4 frame) + The exception is vfork, where the new thread continues to + run on the parent's stack until it calls execve. This could + be a call8 or call12, which requires a legal stack frame + of the previous caller for the overflow handlers to work. + (Note that it's always legal to overflow live registers). + In this case, ensure to spill at least the stack pointer + of that frame. */ + if (clone_flags & CLONE_VM) { - childregs->wmask = 1; /* can't share live windows */ + /* check that caller window is live and same stack */ + int len = childregs->wmask & ~0xf; + if (regs->areg[1] == usp && len != 0) { + int callinc = (regs->areg[0] >> 30) & 3; + int caller_ars = XCHAL_NUM_AREGS - callinc * 4; + put_user(regs->areg[caller_ars+1], + (unsigned __user*)(usp - 12)); + } + childregs->wmask = 1; + childregs->windowstart = 1; + childregs->windowbase = 0; } else { int len = childregs->wmask & ~0xf; memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4], From 3306a72669a2af23b324540b08e68e82ac5b7dab Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 25 Oct 2012 11:10:50 +0400 Subject: [PATCH 4/6] xtensa: switch to generic kernel_thread() Signed-off-by: Max Filippov Signed-off-by: Chris Zankel --- arch/xtensa/Kconfig | 1 + arch/xtensa/include/asm/processor.h | 4 +- arch/xtensa/kernel/entry.S | 41 +++++---------- arch/xtensa/kernel/process.c | 77 +++++++++++++++++------------ arch/xtensa/kernel/xtensa_ksyms.c | 1 - 5 files changed, 61 insertions(+), 63 deletions(-) diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index cdcb48adee4c..9525b70a13a1 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -13,6 +13,7 @@ config XTENSA select GENERIC_CPU_DEVICES select MODULES_USE_ELF_RELA select GENERIC_PCI_IOMAP + select GENERIC_KERNEL_THREAD select ARCH_WANT_OPTIONAL_GPIOLIB help Xtensa processors are 32-bit RISC machines designed by Tensilica diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index 5c371d8d4528..2d630e7399ca 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -152,6 +152,7 @@ struct thread_struct { /* Clearing a0 terminates the backtrace. */ #define start_thread(regs, new_pc, new_sp) \ + memset(regs, 0, sizeof(*regs)); \ regs->pc = new_pc; \ regs->ps = USER_PS_VALUE; \ regs->areg[1] = new_sp; \ @@ -168,9 +169,6 @@ struct mm_struct; /* Free all resources held by a thread. */ #define release_thread(thread) do { } while(0) -/* Create a kernel thread without removing it from tasklists */ -extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags); - /* Copy and release all segment info associated with a VM */ #define copy_segments(p, mm) do { } while(0) #define release_segments(mm) do { } while(0) diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 18453067c258..d4ec1381aebc 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1832,34 +1832,6 @@ ENTRY(system_call) retw -/* - * Create a kernel thread - * - * int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) - * a2 a2 a3 a4 - */ - -ENTRY(kernel_thread) - entry a1, 16 - - mov a5, a2 # preserve fn over syscall - mov a7, a3 # preserve args over syscall - - movi a3, _CLONE_VM | _CLONE_UNTRACED - movi a2, __NR_clone - or a6, a4, a3 # arg0: flags - mov a3, a1 # arg1: sp - syscall - - beq a3, a1, 1f # branch if parent - mov a6, a7 # args - callx4 a5 # fn(args) - - movi a2, __NR_exit - syscall # return value of fn(args) still in a6 - -1: retw - /* * Do a system call from kernel instead of calling sys_execve, so we end up * with proper pt_regs. @@ -1958,3 +1930,16 @@ ENTRY(ret_from_fork) j common_exception_return +/* + * Kernel thread creation helper + * On entry, set up by copy_thread: a2 = thread_fn, a3 = thread_fn arg + * left from _switch_to: a6 = prev + */ +ENTRY(ret_from_kernel_thread) + + call4 schedule_tail + mov a6, a3 + callx4 a2 + call4 do_exit + +ENDPROC(ret_from_kernel_thread) diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index 341c151af919..be52fe437c1b 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -45,6 +45,7 @@ #include extern void ret_from_fork(void); +extern void ret_from_kernel_thread(void); struct task_struct *current_set[NR_CPUS] = {&init_task, }; @@ -158,18 +159,30 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) /* * Copy thread. * + * There are two modes in which this function is called: + * 1) Userspace thread creation, + * regs != NULL, usp_thread_fn is userspace stack pointer. + * It is expected to copy parent regs (in case CLONE_VM is not set + * in the clone_flags) and set up passed usp in the childregs. + * 2) Kernel thread creation, + * regs == NULL, usp_thread_fn is the function to run in the new thread + * and thread_fn_arg is its parameter. + * childregs are not used for the kernel threads. + * * The stack layout for the new thread looks like this: * - * +------------------------+ <- sp in childregs (= tos) + * +------------------------+ * | childregs | * +------------------------+ <- thread.sp = sp in dummy-frame * | dummy-frame | (saved in dummy-frame spill-area) * +------------------------+ * - * We create a dummy frame to return to ret_from_fork: - * a0 points to ret_from_fork (simulating a call4) + * We create a dummy frame to return to either ret_from_fork or + * ret_from_kernel_thread: + * a0 points to ret_from_fork/ret_from_kernel_thread (simulating a call4) * sp points to itself (thread.sp) - * a2, a3 are unused. + * a2, a3 are unused for userspace threads, + * a2 points to thread_fn, a3 holds thread_fn arg for kernel threads. * * Note: This is a pristine frame, so we don't need any spill region on top of * childregs. @@ -185,41 +198,37 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) * involved. Much simpler to just not copy those live frames across. */ -int copy_thread(unsigned long clone_flags, unsigned long usp, - unsigned long unused, - struct task_struct * p, struct pt_regs * regs) +int copy_thread(unsigned long clone_flags, unsigned long usp_thread_fn, + unsigned long thread_fn_arg, + struct task_struct *p, struct pt_regs *unused) { - struct pt_regs *childregs; - unsigned long tos; - int user_mode = user_mode(regs); + struct pt_regs *childregs = task_pt_regs(p); #if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS) struct thread_info *ti; #endif - /* Set up new TSS. */ - tos = (unsigned long)task_stack_page(p) + THREAD_SIZE; - if (user_mode) - childregs = (struct pt_regs*)(tos - PT_USER_SIZE); - else - childregs = (struct pt_regs*)tos - 1; - - /* This does not copy all the regs. In a bout of brilliance or madness, - ARs beyond a0-a15 exist past the end of the struct. */ - *childregs = *regs; - /* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */ *((int*)childregs - 3) = (unsigned long)childregs; *((int*)childregs - 4) = 0; - childregs->areg[2] = 0; - 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)) { + if (!(p->flags & PF_KTHREAD)) { + struct pt_regs *regs = current_pt_regs(); + unsigned long usp = usp_thread_fn ? + usp_thread_fn : regs->areg[1]; + p->thread.ra = MAKE_RA_FOR_CALL( + (unsigned long)ret_from_fork, 0x1); + + /* This does not copy all the regs. + * In a bout of brilliance or madness, + * ARs beyond a0-a15 exist past the end of the struct. + */ + *childregs = *regs; childregs->areg[1] = usp; + childregs->areg[2] = 0; /* When sharing memory with the parent thread, the child usually starts on a pristine stack, so we have to reset @@ -254,11 +263,19 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, // FIXME: we need to set THREADPTR in thread_info... if (clone_flags & CLONE_SETTLS) childregs->areg[2] = childregs->areg[6]; - } else { - /* In kernel space, we start a new thread with a new stack. */ - childregs->wmask = 1; - childregs->areg[1] = tos; + p->thread.ra = MAKE_RA_FOR_CALL( + (unsigned long)ret_from_kernel_thread, 1); + + /* pass parameters to ret_from_kernel_thread: + * a2 = thread_fn, a3 = thread_fn arg + */ + *((int *)childregs - 1) = thread_fn_arg; + *((int *)childregs - 2) = usp_thread_fn; + + /* Childregs are only used when we're going to userspace + * in which case start_thread will set them up. + */ } #if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS) @@ -354,8 +371,6 @@ long xtensa_clone(unsigned long clone_flags, unsigned long newsp, void __user *child_tid, long a5, struct pt_regs *regs) { - if (!newsp) - newsp = regs->areg[1]; return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid); } diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c index a8b9f1fd1e17..afe058b24e6e 100644 --- a/arch/xtensa/kernel/xtensa_ksyms.c +++ b/arch/xtensa/kernel/xtensa_ksyms.c @@ -43,7 +43,6 @@ EXPORT_SYMBOL(__strncpy_user); EXPORT_SYMBOL(clear_page); EXPORT_SYMBOL(copy_page); -EXPORT_SYMBOL(kernel_thread); EXPORT_SYMBOL(empty_zero_page); /* From f0a1bf0859ffa059f9009d6a17e8d46241fb2161 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 25 Oct 2012 11:10:51 +0400 Subject: [PATCH 5/6] xtensa: switch to generic kernel_execve() Signed-off-by: Max Filippov Signed-off-by: Chris Zankel --- arch/xtensa/Kconfig | 1 + arch/xtensa/kernel/entry.S | 18 +----------------- 2 files changed, 2 insertions(+), 17 deletions(-) diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 9525b70a13a1..0d1f36a22c98 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -14,6 +14,7 @@ config XTENSA select MODULES_USE_ELF_RELA select GENERIC_PCI_IOMAP select GENERIC_KERNEL_THREAD + select GENERIC_KERNEL_EXECVE select ARCH_WANT_OPTIONAL_GPIOLIB help Xtensa processors are 32-bit RISC machines designed by Tensilica diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index d4ec1381aebc..90bfc1dbc13d 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1832,22 +1832,6 @@ ENTRY(system_call) retw -/* - * Do a system call from kernel instead of calling sys_execve, so we end up - * with proper pt_regs. - * - * int kernel_execve(const char *fname, char *const argv[], charg *const envp[]) - * a2 a2 a3 a4 - */ - -ENTRY(kernel_execve) - entry a1, 16 - mov a6, a2 # arg0 is in a6 - movi a2, __NR_execve - syscall - - retw - /* * Task switch. * @@ -1940,6 +1924,6 @@ ENTRY(ret_from_kernel_thread) call4 schedule_tail mov a6, a3 callx4 a2 - call4 do_exit + j common_exception_return ENDPROC(ret_from_kernel_thread) From dc241f2c1761bfdec85915f4bbf7e750663f3442 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 25 Oct 2012 11:10:52 +0400 Subject: [PATCH 6/6] xtensa: switch to generic sys_execve() Signed-off-by: Max Filippov Signed-off-by: Chris Zankel --- arch/xtensa/include/asm/syscall.h | 2 +- arch/xtensa/include/asm/unistd.h | 1 + arch/xtensa/include/uapi/asm/unistd.h | 2 +- arch/xtensa/kernel/process.c | 25 ------------------------- 4 files changed, 3 insertions(+), 27 deletions(-) diff --git a/arch/xtensa/include/asm/syscall.h b/arch/xtensa/include/asm/syscall.h index c1dacca312f3..124aeee0d381 100644 --- a/arch/xtensa/include/asm/syscall.h +++ b/arch/xtensa/include/asm/syscall.h @@ -10,7 +10,7 @@ struct pt_regs; struct sigaction; -asmlinkage long xtensa_execve(char*, char**, char**, struct pt_regs*); +asmlinkage long sys_execve(char*, char**, char**, struct pt_regs*); asmlinkage long xtensa_clone(unsigned long, unsigned long, struct pt_regs*); asmlinkage long xtensa_ptrace(long, long, long, long); asmlinkage long xtensa_sigreturn(struct pt_regs*); diff --git a/arch/xtensa/include/asm/unistd.h b/arch/xtensa/include/asm/unistd.h index d9fa52dbfba0..f4e6eaa40d1c 100644 --- a/arch/xtensa/include/asm/unistd.h +++ b/arch/xtensa/include/asm/unistd.h @@ -1,6 +1,7 @@ #ifndef _XTENSA_UNISTD_H #define _XTENSA_UNISTD_H +#define __ARCH_WANT_SYS_EXECVE #include /* diff --git a/arch/xtensa/include/uapi/asm/unistd.h b/arch/xtensa/include/uapi/asm/unistd.h index 1fd157f31211..9f36d0e3e0ac 100644 --- a/arch/xtensa/include/uapi/asm/unistd.h +++ b/arch/xtensa/include/uapi/asm/unistd.h @@ -262,7 +262,7 @@ __SYSCALL(115, sys_sendmmsg, 4) #define __NR_clone 116 __SYSCALL(116, xtensa_clone, 5) #define __NR_execve 117 -__SYSCALL(117, xtensa_execve, 3) +__SYSCALL(117, sys_execve, 3) #define __NR_exit 118 __SYSCALL(118, sys_exit, 1) #define __NR_exit_group 119 diff --git a/arch/xtensa/kernel/process.c b/arch/xtensa/kernel/process.c index be52fe437c1b..09ae7bfab9a7 100644 --- a/arch/xtensa/kernel/process.c +++ b/arch/xtensa/kernel/process.c @@ -373,28 +373,3 @@ long xtensa_clone(unsigned long clone_flags, unsigned long newsp, { return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid); } - -/* - * xtensa_execve() executes a new program. - */ - -asmlinkage -long xtensa_execve(const char __user *name, - const char __user *const __user *argv, - const char __user *const __user *envp, - long a3, long a4, long a5, - struct pt_regs *regs) -{ - long error; - struct filename *filename; - - filename = getname(name); - error = PTR_ERR(filename); - if (IS_ERR(filename)) - goto out; - error = do_execve(filename->name, argv, envp, regs); - putname(filename); -out: - return error; -} -