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SubjectRe: [PATCH 00/13] replace print_symbol() with printk()-s
On (01/05/18 19:21), Sergey Senozhatsky wrote:
> > print_symbol() is an old weird API. It has been
> > obsoleted by printk() and %pS format specifier.
>
> I wouldn't. let's drop the "weird" part.

hm...

you are right, it is weird. and the weird part here is that
print_symbol() is used for things like __show_regs()

print_symbol("PC is at %s\n", instruction_pointer(regs));
print_symbol("LR is at %s\n", regs->ARM_lr);
printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);

or for EMERG error reporting

pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
addr, my_reason->addr);
print_pte(addr);
print_symbol(KERN_EMERG "faulting IP is at %s\n", regs->ip);
print_symbol(KERN_EMERG "last faulting IP was at %s\n", my_reason->ip);
#ifdef __i386__
pr_emerg("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
regs->ax, regs->bx, regs->cx, regs->dx);

or for error reporting in sysfs

print_symbol("fill_read_buffer: %s returned bad count\n",
(unsigned long)ops->show);

and so on.

but, print_symbol() is compiled out on !CONFIG_KALLSYMS systems. so,
basically, we compile out some of errors print outs; even more, on ia64
ia64_do_show_stack() does nothing when there is no CONFIG_KALLSYMS [all
ia64 defconfigs have KALLSYMS_ALL enabled]. printk(%pS), unlike
print_symbol(), is not compiled out and prints the function address
when symbolic name is not available. but, at a glance, print_symbol()
in most of the cases has printk(registers) next to it or before it, so
it doesn't look like we are introducing a regression here by switching
to printk(%pS).

-ss

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