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Commit a3b81113 authored by Robin Getz's avatar Robin Getz Committed by Linus Torvalds
Browse files

remove support for un-needed _extratext section 

When passing a zero address to kallsyms_lookup(), the kernel thought it was
a valid kernel address, even if it is not.  This is because is_ksym_addr()
called is_kernel_extratext() and checked against labels that don't exist on
many archs (which default as zero).  Since PPC was the only kernel which
defines _extra_text, (in 2005), and no longer needs it, this patch removes
_extra_text support.

For some history (provided by Jon):
 http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019734.html
 http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019736.html
 http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019751.html



[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarRobin Getz <rgetz@blackfin.uclinux.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jon Loeliger <jdl@freescale.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0a5dcb51

arch/ppc/kernel/vmlinux.lds.S

+0 −5
Original line number Diff line number Diff line
@@ -143,11 +143,6 @@ SECTIONS 


  . = ALIGN(4096);

  __init_end = .;



  . = ALIGN(4096);

  _sextratext = .;

  _eextratext = .;



  __bss_start = .;

  .bss       :

  {

include/asm-generic/sections.h

+0 −2
Original line number Diff line number Diff line
@@ -8,8 +8,6 @@ extern char _data[], _sdata[], _edata[]; 
extern char __bss_start[], __bss_stop[];

extern char __init_begin[], __init_end[];

extern char _sinittext[], _einittext[];

extern char _sextratext[] __attribute__((weak));

extern char _eextratext[] __attribute__((weak));

extern char _end[];

extern char __per_cpu_start[], __per_cpu_end[];

extern char __kprobes_text_start[], __kprobes_text_end[];

kernel/kallsyms.c

+1 −10
Original line number Diff line number Diff line
@@ -53,14 +53,6 @@ static inline int is_kernel_inittext(unsigned long addr) 
	return 0;

}



static inline int is_kernel_extratext(unsigned long addr)

{

	if (addr >= (unsigned long)_sextratext

	    && addr <= (unsigned long)_eextratext)

		return 1;

	return 0;

}



static inline int is_kernel_text(unsigned long addr)

{

	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
@@ -80,8 +72,7 @@ static int is_ksym_addr(unsigned long addr) 
	if (all_var)

		return is_kernel(addr);



	return is_kernel_text(addr) || is_kernel_inittext(addr) ||

		is_kernel_extratext(addr);

	return is_kernel_text(addr) || is_kernel_inittext(addr);

}



/* expand a compressed symbol data into the resulting uncompressed string,

scripts/kallsyms.c

+10 −14
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ struct sym_entry { 


static struct sym_entry *table;

static unsigned int table_size, table_cnt;

static unsigned long long _text, _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;

static unsigned long long _text, _stext, _etext, _sinittext, _einittext;

static int all_symbols = 0;

static char symbol_prefix_char = '\0';
@@ -99,10 +99,6 @@ static int read_symbol(FILE *in, struct sym_entry *s) 
		_sinittext = s->addr;

	else if (strcmp(sym, "_einittext") == 0)

		_einittext = s->addr;

	else if (strcmp(sym, "_sextratext") == 0)

		_sextratext = s->addr;

	else if (strcmp(sym, "_eextratext") == 0)

		_eextratext = s->addr;

	else if (toupper(stype) == 'A')

	{

		/* Keep these useful absolute symbols */
@@ -165,18 +161,18 @@ static int symbol_valid(struct sym_entry *s) 
	 * and inittext sections are discarded */

	if (!all_symbols) {

		if ((s->addr < _stext || s->addr > _etext)

		    && (s->addr < _sinittext || s->addr > _einittext)

		    && (s->addr < _sextratext || s->addr > _eextratext))

		    && (s->addr < _sinittext || s->addr > _einittext))

			return 0;

		/* Corner case.  Discard any symbols with the same value as

		 * _etext _einittext or _eextratext; they can move between pass

		 * 1 and 2 when the kallsyms data are added.  If these symbols

		 * move then they may get dropped in pass 2, which breaks the

		 * kallsyms rules.

		 * _etext _einittext; they can move between pass 1 and 2 when

		 * the kallsyms data are added.  If these symbols move then

		 * they may get dropped in pass 2, which breaks the kallsyms

		 * rules.

		 */

		if ((s->addr == _etext && strcmp((char*)s->sym + offset, "_etext")) ||

		    (s->addr == _einittext && strcmp((char*)s->sym + offset, "_einittext")) ||

		    (s->addr == _eextratext && strcmp((char*)s->sym + offset, "_eextratext")))

		if ((s->addr == _etext &&

				strcmp((char *)s->sym + offset, "_etext")) ||

		    (s->addr == _einittext &&

				strcmp((char *)s->sym + offset, "_einittext")))

			return 0;

	}