From 07a63cbe8bcb6ba72fb989dcab1ec55ec6c36c7e Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 2 May 2017 13:36:00 +0200 Subject: s390/cputime: fix incorrect system time git commit c5328901aa1db134 "[S390] entry[64].S improvements" removed the update of the exit_timer lowcore field from the critical section cleanup of the .Lsysc_restore/.Lsysc_done and .Lio_restore/.Lio_done blocks. If the PSW is updated by the critical section cleanup to point to user space again, the interrupt entry code will do a vtime calculation after the cleanup completed with an exit_timer value which has *not* been updated. Due to this incorrect system time deltas are calculated. If an interrupt occured with an old PSW between .Lsysc_restore/.Lsysc_done or .Lio_restore/.Lio_done update __LC_EXIT_TIMER with the system entry time of the interrupt. Cc: stable@vger.kernel.org # 3.3+ Tested-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/entry.S | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index a5f5d3bb3dbc..e408d9cc5b96 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -312,6 +312,7 @@ ENTRY(system_call) lg %r14,__LC_VDSO_PER_CPU lmg %r0,%r10,__PT_R0(%r11) mvc __LC_RETURN_PSW(16),__PT_PSW(%r11) +.Lsysc_exit_timer: stpt __LC_EXIT_TIMER mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER lmg %r11,%r15,__PT_R11(%r11) @@ -623,6 +624,7 @@ ENTRY(io_int_handler) lg %r14,__LC_VDSO_PER_CPU lmg %r0,%r10,__PT_R0(%r11) mvc __LC_RETURN_PSW(16),__PT_PSW(%r11) +.Lio_exit_timer: stpt __LC_EXIT_TIMER mvc __VDSO_ECTG_BASE(16,%r14),__LC_EXIT_TIMER lmg %r11,%r15,__PT_R11(%r11) @@ -1174,15 +1176,23 @@ cleanup_critical: br %r14 .Lcleanup_sysc_restore: + # check if stpt has been executed clg %r9,BASED(.Lcleanup_sysc_restore_insn) + jh 0f + mvc __LC_EXIT_TIMER(8),__LC_ASYNC_ENTER_TIMER + cghi %r11,__LC_SAVE_AREA_ASYNC je 0f + mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER +0: clg %r9,BASED(.Lcleanup_sysc_restore_insn+8) + je 1f lg %r9,24(%r11) # get saved pointer to pt_regs mvc __LC_RETURN_PSW(16),__PT_PSW(%r9) mvc 0(64,%r11),__PT_R8(%r9) lmg %r0,%r7,__PT_R0(%r9) -0: lmg %r8,%r9,__LC_RETURN_PSW +1: lmg %r8,%r9,__LC_RETURN_PSW br %r14 .Lcleanup_sysc_restore_insn: + .quad .Lsysc_exit_timer .quad .Lsysc_done - 4 .Lcleanup_io_tif: @@ -1190,15 +1200,20 @@ cleanup_critical: br %r14 .Lcleanup_io_restore: + # check if stpt has been executed clg %r9,BASED(.Lcleanup_io_restore_insn) - je 0f + jh 0f + mvc __LC_EXIT_TIMER(8),__LC_MCCK_ENTER_TIMER +0: clg %r9,BASED(.Lcleanup_io_restore_insn+8) + je 1f lg %r9,24(%r11) # get saved r11 pointer to pt_regs mvc __LC_RETURN_PSW(16),__PT_PSW(%r9) mvc 0(64,%r11),__PT_R8(%r9) lmg %r0,%r7,__PT_R0(%r9) -0: lmg %r8,%r9,__LC_RETURN_PSW +1: lmg %r8,%r9,__LC_RETURN_PSW br %r14 .Lcleanup_io_restore_insn: + .quad .Lio_exit_timer .quad .Lio_done - 4 .Lcleanup_idle: -- cgit v1.2.3 From 085b6ba0f7971d18fc3078b25e8309e9e75659cb Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 2 May 2017 12:38:57 +0200 Subject: s390/ftrace: fix compile for !MODULES Fix this compile error if CONFIG_MODULES is disabled: arch/s390/built-in.o: In function `ftrace_plt_init': arch/s390/kernel/ftrace.o:(.init.text+0x34cc): undefined reference to `module_alloc' Reported-by: Rob Landley Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/ftrace.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch') diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 60a8a4e207ed..68f2b8a15eab 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -172,6 +172,8 @@ int __init ftrace_dyn_arch_init(void) return 0; } +#ifdef CONFIG_MODULES + static int __init ftrace_plt_init(void) { unsigned int *ip; @@ -190,6 +192,8 @@ static int __init ftrace_plt_init(void) } device_initcall(ftrace_plt_init); +#endif /* CONFIG_MODULES */ + #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* * Hook the return address and push it in the stack of return addresses -- cgit v1.2.3 From db55947dd2d09cd3e6f722d1205934fec793ee63 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 2 May 2017 13:20:11 +0200 Subject: s390/uprobes: fix compile for !KPROBES Fix the following compile error(s) if CONFIG_KPROBES is disabled: arch/s390/kernel/uprobes.c:79:14: error: implicit declaration of function 'probe_get_fixup_type' arch/s390/kernel/uprobes.c:87:14: error: 'FIXUP_PSW_NORMAL' undeclared (first use in this function) Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/dis.h | 2 ++ arch/s390/include/asm/kprobes.h | 20 ++++++++++---------- arch/s390/lib/probes.c | 1 + 3 files changed, 13 insertions(+), 10 deletions(-) (limited to 'arch') diff --git a/arch/s390/include/asm/dis.h b/arch/s390/include/asm/dis.h index 60323c21938b..37f617dfbede 100644 --- a/arch/s390/include/asm/dis.h +++ b/arch/s390/include/asm/dis.h @@ -40,6 +40,8 @@ static inline int insn_length(unsigned char code) return ((((int) code + 64) >> 7) + 1) << 1; } +struct pt_regs; + void show_code(struct pt_regs *regs); void print_fn_code(unsigned char *code, unsigned long len); int insn_to_mnemonic(unsigned char *instruction, char *buf, unsigned int len); diff --git a/arch/s390/include/asm/kprobes.h b/arch/s390/include/asm/kprobes.h index 1293c4066cfc..28792ef82c83 100644 --- a/arch/s390/include/asm/kprobes.h +++ b/arch/s390/include/asm/kprobes.h @@ -27,12 +27,21 @@ * 2005-Dec Used as a template for s390 by Mike Grundy * */ +#include #include #define BREAKPOINT_INSTRUCTION 0x0002 +#define FIXUP_PSW_NORMAL 0x08 +#define FIXUP_BRANCH_NOT_TAKEN 0x04 +#define FIXUP_RETURN_REGISTER 0x02 +#define FIXUP_NOT_REQUIRED 0x01 + +int probe_is_prohibited_opcode(u16 *insn); +int probe_get_fixup_type(u16 *insn); +int probe_is_insn_relative_long(u16 *insn); + #ifdef CONFIG_KPROBES -#include #include #include #include @@ -56,11 +65,6 @@ typedef u16 kprobe_opcode_t; #define KPROBE_SWAP_INST 0x10 -#define FIXUP_PSW_NORMAL 0x08 -#define FIXUP_BRANCH_NOT_TAKEN 0x04 -#define FIXUP_RETURN_REGISTER 0x02 -#define FIXUP_NOT_REQUIRED 0x01 - /* Architecture specific copy of original instruction */ struct arch_specific_insn { /* copy of original instruction */ @@ -90,10 +94,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr); int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); -int probe_is_prohibited_opcode(u16 *insn); -int probe_get_fixup_type(u16 *insn); -int probe_is_insn_relative_long(u16 *insn); - #define flush_insn_slot(p) do { } while (0) #endif /* CONFIG_KPROBES */ diff --git a/arch/s390/lib/probes.c b/arch/s390/lib/probes.c index ae90e1ae3607..1963ddbf4ab3 100644 --- a/arch/s390/lib/probes.c +++ b/arch/s390/lib/probes.c @@ -4,6 +4,7 @@ * Copyright IBM Corp. 2014 */ +#include #include #include -- cgit v1.2.3 From f5c8b9601036869e162cb278aaafbf003dc4e5a0 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Wed, 3 May 2017 09:15:07 +0200 Subject: s390/uaccess: use sane length for __strncpy_from_user() The average string that is copied from user space to kernel space is rather short. E.g. booting a system involves about 50.000 strncpy_from_user() calls where the NULL terminated string has an average size of 27 bytes. By default our s390 specific strncpy_from_user() implementation however copies up to 4096 bytes, which is a waste of cpu cycles and cache lines. Therefore reduce the default length to L1_CACHE_BYTES (256 bytes), which also reduces the average execution time of strncpy_from_user() by 30-40%. Alternatively we could have switched to the generic strncpy_from_user() implementation, however it turned out that that variant would be slower than the now optimized s390 variant. Reported-by: Al Viro Reported-by: Linus Torvalds Signed-off-by: Heiko Carstens Reviewed-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky --- arch/s390/lib/uaccess.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c index 1e5bb2b86c42..b3bd3f23b8e8 100644 --- a/arch/s390/lib/uaccess.c +++ b/arch/s390/lib/uaccess.c @@ -337,8 +337,8 @@ long __strncpy_from_user(char *dst, const char __user *src, long size) return 0; done = 0; do { - offset = (size_t)src & ~PAGE_MASK; - len = min(size - done, PAGE_SIZE - offset); + offset = (size_t)src & (L1_CACHE_BYTES - 1); + len = min(size - done, L1_CACHE_BYTES - offset); if (copy_from_user(dst, src, len)) return -EFAULT; len_str = strnlen(dst, len); -- cgit v1.2.3 From 80ba38469aa28bbcfc7a31e5b41adfc42120465e Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 4 May 2017 13:06:58 +0200 Subject: s390/topology: let topology_mnest_limit() return unsigned char Fixes a couple of compile warnings with gcc 7.1.0 : arch/s390/kernel/sysinfo.c:578:20: note: directive argument in the range [-2147483648, 4] sprintf(link_to, "15_1_%d", topology_mnest_limit()); Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/sysinfo.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/include/asm/sysinfo.h b/arch/s390/include/asm/sysinfo.h index 73bff45ced55..e784bed6ed7f 100644 --- a/arch/s390/include/asm/sysinfo.h +++ b/arch/s390/include/asm/sysinfo.h @@ -146,7 +146,7 @@ extern int topology_max_mnest; * Returns the maximum nesting level supported by the cpu topology code. * The current maximum level is 4 which is the drawer level. */ -static inline int topology_mnest_limit(void) +static inline unsigned char topology_mnest_limit(void) { return min(topology_max_mnest, 4); } -- cgit v1.2.3 From d04a4c76f71dd5335f8e499b59617382d84e2b8d Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 4 May 2017 09:42:22 +0200 Subject: s390: move _text symbol to address higher than zero The perf tool assumes that kernel symbols are never present at address zero. In fact it assumes if functions that map symbols to addresses return zero, that the symbol was not found. Given that s390's _text symbol historically is located at address zero this yields at least a couple of false errors and warnings in one of perf's test cases about not present symbols ("perf test 1"). To fix this simply move the _text symbol to address 0x200, just behind the initial psw and channel program located at the beginning of the kernel image. This is now hard coded within the linker script. I tried a nicer solution which moves the initial psw and channel program into an own section. However that would move the symbols within the "real" head.text section to different addresses, since the ".org" statements within head.S are relative to the head.text section. If there is a new section in front, everything else will be moved. Alternatively I could have adjusted all ".org" statements. But this current solution seems to be the easiest one, since nobody really cares where the _text symbol is actually located. Reported-by: Zvonko Kosic Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/vmlinux.lds.S | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 72307f108c40..6e2c42bd1c3b 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -31,8 +31,14 @@ SECTIONS { . = 0x00000000; .text : { - _text = .; /* Text and read-only data */ + /* Text and read-only data */ HEAD_TEXT + /* + * E.g. perf doesn't like symbols starting at address zero, + * therefore skip the initial PSW and channel program located + * at address zero and let _text start at 0x200. + */ + _text = 0x200; TEXT_TEXT SCHED_TEXT CPUIDLE_TEXT -- cgit v1.2.3 From efc0c21c9ea786d6f019d7df7b4e3932f3578d90 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Thu, 2 Mar 2017 12:23:45 +0100 Subject: s390: convert debug_info.ref_count from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/debug.h | 3 ++- arch/s390/kernel/debug.c | 8 ++++---- 2 files changed, 6 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/s390/include/asm/debug.h b/arch/s390/include/asm/debug.h index 0206c8052328..df7b54ea956d 100644 --- a/arch/s390/include/asm/debug.h +++ b/arch/s390/include/asm/debug.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #define DEBUG_MAX_LEVEL 6 /* debug levels range from 0 to 6 */ @@ -31,7 +32,7 @@ struct debug_view; typedef struct debug_info { struct debug_info* next; struct debug_info* prev; - atomic_t ref_count; + refcount_t ref_count; spinlock_t lock; int level; int nr_areas; diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c index 530226b6cb19..86b3e74f569e 100644 --- a/arch/s390/kernel/debug.c +++ b/arch/s390/kernel/debug.c @@ -277,7 +277,7 @@ debug_info_alloc(const char *name, int pages_per_area, int nr_areas, memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *)); memset(rc->debugfs_entries, 0 ,DEBUG_MAX_VIEWS * sizeof(struct dentry*)); - atomic_set(&(rc->ref_count), 0); + refcount_set(&(rc->ref_count), 0); return rc; @@ -361,7 +361,7 @@ debug_info_create(const char *name, int pages_per_area, int nr_areas, debug_area_last = rc; rc->next = NULL; - debug_info_get(rc); + refcount_set(&rc->ref_count, 1); out: return rc; } @@ -416,7 +416,7 @@ static void debug_info_get(debug_info_t * db_info) { if (db_info) - atomic_inc(&db_info->ref_count); + refcount_inc(&db_info->ref_count); } /* @@ -431,7 +431,7 @@ debug_info_put(debug_info_t *db_info) if (!db_info) return; - if (atomic_dec_and_test(&db_info->ref_count)) { + if (refcount_dec_and_test(&db_info->ref_count)) { for (i = 0; i < DEBUG_MAX_VIEWS; i++) { if (!db_info->views[i]) continue; -- cgit v1.2.3