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authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-01 13:36:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-01 13:36:15 -0800
commitab486bc9a591689f3ac2b6ebc072309371f8f451 (patch)
treebe319be4bc727e61c83b033caf8339e6b4acfb2b /arch/ia64
parent34b1cf60abb06fa79d5f8e56f1def843dbf91888 (diff)
parentbb4f552a598d40624343bc0815e594efd4d6ec3d (diff)
downloadlinux-ab486bc9a591689f3ac2b6ebc072309371f8f451.tar.bz2
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek: - Add a console_msg_format command line option: The value "default" keeps the old "[time stamp] text\n" format. The value "syslog" allows to see the syslog-like "<log level>[timestamp] text" format. This feature was requested by people doing regression tests, for example, 0day robot. They want to have both filtered and full logs at hands. - Reduce the risk of softlockup: Pass the console owner in a busy loop. This is a new approach to the old problem. It was first proposed by Steven Rostedt on Kernel Summit 2017. It marks a context in which the console_lock owner calls console drivers and could not sleep. On the other side, printk() callers could detect this state and use a busy wait instead of a simple console_trylock(). Finally, the console_lock owner checks if there is a busy waiter at the end of the special context and eventually passes the console_lock to the waiter. The hand-off works surprisingly well and helps in many situations. Well, there is still a possibility of the softlockup, for example, when the flood of messages stops and the last owner still has too much to flush. There is increasing number of people having problems with printk-related softlockups. We might eventually need to get better solution. Anyway, this looks like a good start and promising direction. - Do not allow to schedule in console_unlock() called from printk(): This reverts an older controversial commit. The reschedule helped to avoid softlockups. But it also slowed down the console output. This patch is obsoleted by the new console waiter logic described above. In fact, the reschedule made the hand-off less effective. - Deprecate "%pf" and "%pF" format specifier: It was needed on ia64, ppc64 and parisc64 to dereference function descriptors and show the real function address. It is done transparently by "%ps" and "pS" format specifier now. Sergey Senozhatsky found that all the function descriptors were in a special elf section and could be easily detected. - Remove printk_symbol() API: It has been obsoleted by "%pS" format specifier, and this change helped to remove few continuous lines and a less intuitive old API. - Remove redundant memsets: Sergey removed unnecessary memset when processing printk.devkmsg command line option. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits) printk: drop redundant devkmsg_log_str memsets printk: Never set console_may_schedule in console_trylock() printk: Hide console waiter logic into helpers printk: Add console owner and waiter logic to load balance console writes kallsyms: remove print_symbol() function checkpatch: add pF/pf deprecation warning symbol lookup: introduce dereference_symbol_descriptor() parisc64: Add .opd based function descriptor dereference powerpc64: Add .opd based function descriptor dereference ia64: Add .opd based function descriptor dereference sections: split dereference_function_descriptor() openrisc: Fix conflicting types for _exext and _stext lib: do not use print_symbol() irq debug: do not use print_symbol() sysfs: do not use print_symbol() drivers: do not use print_symbol() x86: do not use print_symbol() unicore32: do not use print_symbol() sh: do not use print_symbol() mn10300: do not use print_symbol() ...
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/include/asm/sections.h10
-rw-r--r--arch/ia64/kernel/module.c12
-rw-r--r--arch/ia64/kernel/process.c10
-rw-r--r--arch/ia64/kernel/vmlinux.lds.S2
4 files changed, 26 insertions, 8 deletions
diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index f3481408594e..cea15f2dd38d 100644
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h
@@ -27,6 +27,8 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b
extern char __start_unwind[], __end_unwind[];
extern char __start_ivt_text[], __end_ivt_text[];
+#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
+
#undef dereference_function_descriptor
static inline void *dereference_function_descriptor(void *ptr)
{
@@ -38,6 +40,12 @@ static inline void *dereference_function_descriptor(void *ptr)
return ptr;
}
+#undef dereference_kernel_function_descriptor
+static inline void *dereference_kernel_function_descriptor(void *ptr)
+{
+ if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
+ return ptr;
+ return dereference_function_descriptor(ptr);
+}
#endif /* _ASM_IA64_SECTIONS_H */
-
diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c
index 853b5611a894..326448f9df16 100644
--- a/arch/ia64/kernel/module.c
+++ b/arch/ia64/kernel/module.c
@@ -36,6 +36,7 @@
#include <asm/patch.h>
#include <asm/unaligned.h>
+#include <asm/sections.h>
#define ARCH_MODULE_DEBUG 0
@@ -918,3 +919,14 @@ module_arch_cleanup (struct module *mod)
if (mod->arch.core_unw_table)
unw_remove_unwind_table(mod->arch.core_unw_table);
}
+
+void *dereference_module_function_descriptor(struct module *mod, void *ptr)
+{
+ Elf64_Shdr *opd = mod->arch.opd;
+
+ if (ptr < (void *)opd->sh_addr ||
+ ptr >= (void *)(opd->sh_addr + opd->sh_size))
+ return ptr;
+
+ return dereference_function_descriptor(ptr);
+}
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index dda0082056b3..968b5f33e725 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -13,7 +13,6 @@
#include <linux/pm.h>
#include <linux/elf.h>
#include <linux/errno.h>
-#include <linux/kallsyms.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
@@ -69,7 +68,6 @@ void
ia64_do_show_stack (struct unw_frame_info *info, void *arg)
{
unsigned long ip, sp, bsp;
- char buf[128]; /* don't make it so big that it overflows the stack! */
printk("\nCall Trace:\n");
do {
@@ -79,11 +77,9 @@ ia64_do_show_stack (struct unw_frame_info *info, void *arg)
unw_get_sp(info, &sp);
unw_get_bsp(info, &bsp);
- snprintf(buf, sizeof(buf),
- " [<%016lx>] %%s\n"
+ printk(" [<%016lx>] %pS\n"
" sp=%016lx bsp=%016lx\n",
- ip, sp, bsp);
- print_symbol(buf, ip);
+ ip, (void *)ip, sp, bsp);
} while (unw_unwind(info) >= 0);
}
@@ -111,7 +107,7 @@ show_regs (struct pt_regs *regs)
printk("psr : %016lx ifs : %016lx ip : [<%016lx>] %s (%s)\n",
regs->cr_ipsr, regs->cr_ifs, ip, print_tainted(),
init_utsname()->release);
- print_symbol("ip is at %s\n", ip);
+ printk("ip is at %pS\n", (void *)ip);
printk("unat: %016lx pfs : %016lx rsc : %016lx\n",
regs->ar_unat, regs->ar_pfs, regs->ar_rsc);
printk("rnat: %016lx bsps: %016lx pr : %016lx\n",
diff --git a/arch/ia64/kernel/vmlinux.lds.S b/arch/ia64/kernel/vmlinux.lds.S
index b0b2070e0591..0da58cf8e213 100644
--- a/arch/ia64/kernel/vmlinux.lds.S
+++ b/arch/ia64/kernel/vmlinux.lds.S
@@ -109,7 +109,9 @@ SECTIONS {
RODATA
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
+ __start_opd = .;
*(.opd)
+ __end_opd = .;
}
/*