From 184748cc50b2dceb8287f9fb657eda48ff8fcfe7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 5 Apr 2011 17:23:39 +0200 Subject: sched: Provide scheduler_ipi() callback in response to smp_send_reschedule() For future rework of try_to_wake_up() we'd like to push part of that function onto the CPU the task is actually going to run on. In order to do so we need a generic callback from the existing scheduler IPI. This patch introduces such a generic callback: scheduler_ipi() and implements it as a NOP. BenH notes: PowerPC might use this IPI on offline CPUs under rare conditions! Acked-by: Russell King Acked-by: Martin Schwidefsky Acked-by: Chris Metcalf Acked-by: Jesper Nilsson Acked-by: Benjamin Herrenschmidt Signed-off-by: Ralf Baechle Reviewed-by: Frank Rowand Cc: Mike Galbraith Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110405152728.744338123@chello.nl --- arch/um/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/um') diff --git a/arch/um/kernel/smp.c b/arch/um/kernel/smp.c index 106bf27e2a9a..eefb107d2d73 100644 --- a/arch/um/kernel/smp.c +++ b/arch/um/kernel/smp.c @@ -173,7 +173,7 @@ void IPI_handler(int cpu) break; case 'R': - set_tsk_need_resched(current); + scheduler_ipi(); break; case 'S': -- cgit v1.2.1 From 57d8e02e3cd21bccf2b84b26b42feb79e1f0f83e Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Wed, 27 Apr 2011 15:26:51 -0700 Subject: um: mdd support for 64 bit atomic operations This adds support for 64 bit atomic operations on 32 bit UML systems. XFS needs them since 2.6.38. $ make ARCH=um SUBARCH=i386 ... LD .tmp_vmlinux1 fs/built-in.o: In function `xlog_regrant_reserve_log_space': xfs_log.c:(.text+0xd8584): undefined reference to `atomic64_read_386' xfs_log.c:(.text+0xd85ac): undefined reference to `cmpxchg8b_emu' ... Addresses https://bugzilla.kernel.org/show_bug.cgi?id=32812 Reported-by: Martin Walch Tested-by: Martin Walch Cc: Martin Walch Cc: [2.6.38.x 084189a: um: disable CONFIG_CMPXCHG_LOCAL] Signed-off-by: Richard Weinberger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/sys-i386/Makefile | 2 +- arch/um/sys-i386/atomic64_cx8_32.S | 225 +++++++++++++++++++++++++++++++++++++ 2 files changed, 226 insertions(+), 1 deletion(-) create mode 100644 arch/um/sys-i386/atomic64_cx8_32.S (limited to 'arch/um') diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile index 804b28dd0328..b1da91c1b200 100644 --- a/arch/um/sys-i386/Makefile +++ b/arch/um/sys-i386/Makefile @@ -4,7 +4,7 @@ obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \ ptrace_user.o setjmp.o signal.o stub.o stub_segv.o syscalls.o sysrq.o \ - sys_call_table.o tls.o + sys_call_table.o tls.o atomic64_cx8_32.o obj-$(CONFIG_BINFMT_ELF) += elfcore.o diff --git a/arch/um/sys-i386/atomic64_cx8_32.S b/arch/um/sys-i386/atomic64_cx8_32.S new file mode 100644 index 000000000000..1e901d3d4a95 --- /dev/null +++ b/arch/um/sys-i386/atomic64_cx8_32.S @@ -0,0 +1,225 @@ +/* + * atomic64_t for 586+ + * + * Copied from arch/x86/lib/atomic64_cx8_32.S + * + * Copyright © 2010 Luca Barbieri + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include +#include +#include + +.macro SAVE reg + pushl_cfi %\reg + CFI_REL_OFFSET \reg, 0 +.endm + +.macro RESTORE reg + popl_cfi %\reg + CFI_RESTORE \reg +.endm + +.macro read64 reg + movl %ebx, %eax + movl %ecx, %edx +/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */ + LOCK_PREFIX + cmpxchg8b (\reg) +.endm + +ENTRY(atomic64_read_cx8) + CFI_STARTPROC + + read64 %ecx + ret + CFI_ENDPROC +ENDPROC(atomic64_read_cx8) + +ENTRY(atomic64_set_cx8) + CFI_STARTPROC + +1: +/* we don't need LOCK_PREFIX since aligned 64-bit writes + * are atomic on 586 and newer */ + cmpxchg8b (%esi) + jne 1b + + ret + CFI_ENDPROC +ENDPROC(atomic64_set_cx8) + +ENTRY(atomic64_xchg_cx8) + CFI_STARTPROC + + movl %ebx, %eax + movl %ecx, %edx +1: + LOCK_PREFIX + cmpxchg8b (%esi) + jne 1b + + ret + CFI_ENDPROC +ENDPROC(atomic64_xchg_cx8) + +.macro addsub_return func ins insc +ENTRY(atomic64_\func\()_return_cx8) + CFI_STARTPROC + SAVE ebp + SAVE ebx + SAVE esi + SAVE edi + + movl %eax, %esi + movl %edx, %edi + movl %ecx, %ebp + + read64 %ebp +1: + movl %eax, %ebx + movl %edx, %ecx + \ins\()l %esi, %ebx + \insc\()l %edi, %ecx + LOCK_PREFIX + cmpxchg8b (%ebp) + jne 1b + +10: + movl %ebx, %eax + movl %ecx, %edx + RESTORE edi + RESTORE esi + RESTORE ebx + RESTORE ebp + ret + CFI_ENDPROC +ENDPROC(atomic64_\func\()_return_cx8) +.endm + +addsub_return add add adc +addsub_return sub sub sbb + +.macro incdec_return func ins insc +ENTRY(atomic64_\func\()_return_cx8) + CFI_STARTPROC + SAVE ebx + + read64 %esi +1: + movl %eax, %ebx + movl %edx, %ecx + \ins\()l $1, %ebx + \insc\()l $0, %ecx + LOCK_PREFIX + cmpxchg8b (%esi) + jne 1b + +10: + movl %ebx, %eax + movl %ecx, %edx + RESTORE ebx + ret + CFI_ENDPROC +ENDPROC(atomic64_\func\()_return_cx8) +.endm + +incdec_return inc add adc +incdec_return dec sub sbb + +ENTRY(atomic64_dec_if_positive_cx8) + CFI_STARTPROC + SAVE ebx + + read64 %esi +1: + movl %eax, %ebx + movl %edx, %ecx + subl $1, %ebx + sbb $0, %ecx + js 2f + LOCK_PREFIX + cmpxchg8b (%esi) + jne 1b + +2: + movl %ebx, %eax + movl %ecx, %edx + RESTORE ebx + ret + CFI_ENDPROC +ENDPROC(atomic64_dec_if_positive_cx8) + +ENTRY(atomic64_add_unless_cx8) + CFI_STARTPROC + SAVE ebp + SAVE ebx +/* these just push these two parameters on the stack */ + SAVE edi + SAVE esi + + movl %ecx, %ebp + movl %eax, %esi + movl %edx, %edi + + read64 %ebp +1: + cmpl %eax, 0(%esp) + je 4f +2: + movl %eax, %ebx + movl %edx, %ecx + addl %esi, %ebx + adcl %edi, %ecx + LOCK_PREFIX + cmpxchg8b (%ebp) + jne 1b + + movl $1, %eax +3: + addl $8, %esp + CFI_ADJUST_CFA_OFFSET -8 + RESTORE ebx + RESTORE ebp + ret +4: + cmpl %edx, 4(%esp) + jne 2b + xorl %eax, %eax + jmp 3b + CFI_ENDPROC +ENDPROC(atomic64_add_unless_cx8) + +ENTRY(atomic64_inc_not_zero_cx8) + CFI_STARTPROC + SAVE ebx + + read64 %esi +1: + testl %eax, %eax + je 4f +2: + movl %eax, %ebx + movl %edx, %ecx + addl $1, %ebx + adcl $0, %ecx + LOCK_PREFIX + cmpxchg8b (%esi) + jne 1b + + movl $1, %eax +3: + RESTORE ebx + ret +4: + testl %edx, %edx + jne 2b + jmp 3b + CFI_ENDPROC +ENDPROC(atomic64_inc_not_zero_cx8) -- cgit v1.2.1 From 365a0deae2b6743b3263a71871bbd8c9f66ac34c Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Wed, 27 Apr 2011 15:26:53 -0700 Subject: uml: fix hppfs build Make HoneyPot ProcFS depend on CONFIG_PROC_FS so that it will build. Recommended by Christoph Hellwig. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=33692 Reported-by: Simon Danner Signed-off-by: Randy Dunlap Cc: Jeff Dike Cc: Christoph Hellwig Signed-off-by: Richard Weinberger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/Kconfig.um | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/um') diff --git a/arch/um/Kconfig.um b/arch/um/Kconfig.um index 90a438acbfaf..b5e675e370c6 100644 --- a/arch/um/Kconfig.um +++ b/arch/um/Kconfig.um @@ -47,7 +47,7 @@ config HOSTFS config HPPFS tristate "HoneyPot ProcFS (EXPERIMENTAL)" - depends on EXPERIMENTAL + depends on EXPERIMENTAL && PROC_FS help hppfs (HoneyPot ProcFS) is a filesystem which allows UML /proc entries to be overridden, removed, or fabricated from the host. -- cgit v1.2.1 From 534e3adbd22efa327e6ff27cf2d8ebaad8382ecd Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Wed, 27 Apr 2011 15:26:54 -0700 Subject: um: adjust current_thread_info() for newer gcc versions In some cases gcc >= 4.5.2 will optimize away current_thread_info(). To prevent gcc from doing so the stack address has to be obtained via inline asm. Signed-off-by: Richard Weinberger Acked-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/asm/thread_info.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/um') diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h index e2cf786bda0a..5bd1bad33fab 100644 --- a/arch/um/include/asm/thread_info.h +++ b/arch/um/include/asm/thread_info.h @@ -49,7 +49,10 @@ static inline struct thread_info *current_thread_info(void) { struct thread_info *ti; unsigned long mask = THREAD_SIZE - 1; - ti = (struct thread_info *) (((unsigned long) &ti) & ~mask); + void *p; + + asm volatile ("" : "=r" (p) : "0" (&ti)); + ti = (struct thread_info *) (((unsigned long)p) & ~mask); return ti; } -- cgit v1.2.1 From b2db21997f43907f54500edaf063253ca2a186f9 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Tue, 17 May 2011 15:44:11 -0700 Subject: um: fix abort os_dump_core() uses abort() to terminate UML in case of an fatal error. glibc's abort() calls raise(SIGABRT) which makes use of tgkill(). tgkill() has no effect within UML's kernel threads because they are not pthreads. As fallback abort() executes an invalid instruction to terminate the process. Therefore UML gets killed by SIGSEGV and leaves a ugly log entry in the host's kernel ring buffer. To get rid of this we use our own abort routine. Signed-off-by: Richard Weinberger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/util.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'arch/um') diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c index 6ea77979531c..42827cafa6af 100644 --- a/arch/um/os-Linux/util.c +++ b/arch/um/os-Linux/util.c @@ -5,6 +5,7 @@ #include #include +#include #include #include #include @@ -75,6 +76,26 @@ void setup_hostinfo(char *buf, int len) host.release, host.version, host.machine); } +/* + * We cannot use glibc's abort(). It makes use of tgkill() which + * has no effect within UML's kernel threads. + * After that glibc would execute an invalid instruction to kill + * the calling process and UML crashes with SIGSEGV. + */ +static inline void __attribute__ ((noreturn)) uml_abort(void) +{ + sigset_t sig; + + fflush(NULL); + + if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT)) + sigprocmask(SIG_UNBLOCK, &sig, 0); + + for (;;) + if (kill(getpid(), SIGABRT) < 0) + exit(127); +} + void os_dump_core(void) { int pid; @@ -116,5 +137,5 @@ void os_dump_core(void) while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0) os_kill_ptraced_process(pid, 0); - abort(); + uml_abort(); } -- cgit v1.2.1