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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH, v2] x86-64: reduce symbol table size
With all of Xen's symbols sitting within a 2Gb range on x86-64, they
can be referred to by the kallsyms-like offset table using 4- instead
of 8-byte slots.
The marker table can use 4-byte slots in all cases, just like the table
entry counts can (though that's only a minor improvement).
If ia64's PERCPU_ADDR got moved down to (KERNEL_START + 2Gb -
PERCPU_PAGE_SIZE), it could also utilize the more compact form.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
--- 2009-07-10.orig/xen/common/symbols.c 2009-07-13 13:56:07.000000000
+0200
+++ 2009-07-10/xen/common/symbols.c 2009-06-30 16:58:32.000000000 +0200
@@ -18,21 +18,27 @@
#include <xen/string.h>
#include <xen/spinlock.h>
-extern unsigned long symbols_addresses[];
-extern unsigned long symbols_num_syms;
-extern u8 symbols_names[];
+#ifdef SYMBOLS_ORIGIN
+extern const unsigned int symbols_offsets[1];
+#define symbols_address(n) (SYMBOLS_ORIGIN + symbols_offsets[n])
+#else
+extern const unsigned long symbols_addresses[];
+#define symbols_address(n) symbols_addresses[n]
+#endif
+extern const unsigned int symbols_num_syms;
+extern const u8 symbols_names[];
-extern u8 symbols_token_table[];
-extern u16 symbols_token_index[];
+extern const u8 symbols_token_table[];
+extern const u16 symbols_token_index[];
-extern unsigned long symbols_markers[];
+extern const unsigned int symbols_markers[];
/* expand a compressed symbol data into the resulting uncompressed string,
given the offset to where the symbol is in the compressed stream */
static unsigned int symbols_expand_symbol(unsigned int off, char *result)
{
int len, skipped_first = 0;
- u8 *tptr, *data;
+ const u8 *tptr, *data;
/* get the compressed symbol length from the first symbol byte */
data = &symbols_names[off];
@@ -70,7 +76,7 @@ static unsigned int symbols_expand_symbo
* symbols array */
static unsigned int get_symbol_offset(unsigned long pos)
{
- u8 *name;
+ const u8 *name;
int i;
/* use the closest marker we have. We have markers every 256 positions,
@@ -107,13 +113,13 @@ const char *symbols_lookup(unsigned long
while (high-low > 1) {
mid = (low + high) / 2;
- if (symbols_addresses[mid] <= addr) low = mid;
+ if (symbols_address(mid) <= addr) low = mid;
else high = mid;
}
/* search for the first aliased symbol. Aliased symbols are
symbols with the same address */
- while (low && symbols_addresses[low - 1] == symbols_addresses[low])
+ while (low && symbols_address(low - 1) == symbols_address(low))
--low;
/* Grab name */
@@ -121,8 +127,8 @@ const char *symbols_lookup(unsigned long
/* Search for next non-aliased symbol */
for (i = low + 1; i < symbols_num_syms; i++) {
- if (symbols_addresses[i] > symbols_addresses[low]) {
- symbol_end = symbols_addresses[i];
+ if (symbols_address(i) > symbols_address(low)) {
+ symbol_end = symbols_address(i);
break;
}
}
@@ -132,8 +138,8 @@ const char *symbols_lookup(unsigned long
symbol_end = is_kernel_inittext(addr) ?
(unsigned long)_einittext : (unsigned long)_etext;
- *symbolsize = symbol_end - symbols_addresses[low];
- *offset = addr - symbols_addresses[low];
+ *symbolsize = symbol_end - symbols_address(low);
+ *offset = addr - symbols_address(low);
return namebuf;
}
--- 2009-07-10.orig/xen/common/symbols-dummy.c 2009-07-13 13:56:07.000000000
+0200
+++ 2009-07-10/xen/common/symbols-dummy.c 2009-06-30 16:55:43.000000000
+0200
@@ -6,11 +6,15 @@
#include <xen/config.h>
#include <xen/types.h>
-unsigned long symbols_addresses[1];
-unsigned long symbols_num_syms;
-u8 symbols_names[1];
+#ifdef SYMBOLS_ORIGIN
+const unsigned int symbols_offsets[1];
+#else
+const unsigned long symbols_addresses[1];
+#endif
+const unsigned int symbols_num_syms;
+const u8 symbols_names[1];
-u8 symbols_token_table[1];
-u16 symbols_token_index[1];
+const u8 symbols_token_table[1];
+const u16 symbols_token_index[1];
-unsigned long symbols_markers[1];
+const unsigned int symbols_markers[1];
--- 2009-07-10.orig/xen/include/asm-x86/config.h 2009-07-13
13:56:07.000000000 +0200
+++ 2009-07-10/xen/include/asm-x86/config.h 2009-07-13 14:01:35.000000000
+0200
@@ -122,10 +122,12 @@ extern unsigned int video_mode, video_fl
#define PML4_ADDR(_slot) \
((((_slot ## UL) >> 8) * 0xffff000000000000UL) | \
(_slot ## UL << PML4_ENTRY_BITS))
+#define GB(_gb) (_gb ## UL << 30)
#else
#define PML4_ENTRY_BYTES (1 << PML4_ENTRY_BITS)
#define PML4_ADDR(_slot) \
(((_slot >> 8) * 0xffff000000000000) | (_slot << PML4_ENTRY_BITS))
+#define GB(_gb) (_gb << 30)
#endif
/*
@@ -210,22 +212,22 @@ extern unsigned int video_mode, video_fl
#define PERDOMAIN_MBYTES (PML4_ENTRY_BYTES >> (20 + PAGETABLE_ORDER))
/* Slot 261: machine-to-phys conversion table (16GB). */
#define RDWR_MPT_VIRT_START (PML4_ADDR(261))
-#define RDWR_MPT_VIRT_END (RDWR_MPT_VIRT_START + (16UL<<30))
+#define RDWR_MPT_VIRT_END (RDWR_MPT_VIRT_START + GB(16))
/* Slot 261: page-frame information array (16GB). */
#define FRAMETABLE_VIRT_START (RDWR_MPT_VIRT_END)
-#define FRAMETABLE_VIRT_END (FRAMETABLE_VIRT_START + (16UL<<30))
+#define FRAMETABLE_VIRT_END (FRAMETABLE_VIRT_START + GB(16))
/* Slot 261: ioremap()/fixmap area (16GB). */
#define IOREMAP_VIRT_START (FRAMETABLE_VIRT_END)
-#define IOREMAP_VIRT_END (IOREMAP_VIRT_START + (16UL<<30))
+#define IOREMAP_VIRT_END (IOREMAP_VIRT_START + GB(16))
/* Slot 261: compatibility machine-to-phys conversion table (1GB). */
#define RDWR_COMPAT_MPT_VIRT_START IOREMAP_VIRT_END
-#define RDWR_COMPAT_MPT_VIRT_END (RDWR_COMPAT_MPT_VIRT_START + (1UL << 30))
+#define RDWR_COMPAT_MPT_VIRT_END (RDWR_COMPAT_MPT_VIRT_START + GB(1))
/* Slot 261: high read-only compat machine-to-phys conversion table (1GB). */
#define HIRO_COMPAT_MPT_VIRT_START RDWR_COMPAT_MPT_VIRT_END
-#define HIRO_COMPAT_MPT_VIRT_END (HIRO_COMPAT_MPT_VIRT_START + (1UL << 30))
+#define HIRO_COMPAT_MPT_VIRT_END (HIRO_COMPAT_MPT_VIRT_START + GB(1))
/* Slot 261: xen text, static data and bss (1GB). */
#define XEN_VIRT_START (HIRO_COMPAT_MPT_VIRT_END)
-#define XEN_VIRT_END (XEN_VIRT_START + (1UL << 30))
+#define XEN_VIRT_END (XEN_VIRT_START + GB(1))
/* Slot 262-263: A direct 1:1 mapping of all of physical memory. */
#define DIRECTMAP_VIRT_START (PML4_ADDR(262))
#define DIRECTMAP_VIRT_END (DIRECTMAP_VIRT_START + PML4_ENTRY_BYTES*2)
@@ -259,6 +261,8 @@ extern unsigned int video_mode, video_fl
#define __HYPERVISOR_DS32 0xe010
#define __HYPERVISOR_DS __HYPERVISOR_DS64
+#define SYMBOLS_ORIGIN XEN_VIRT_START
+
/* For generic assembly code: use macros to define operation/operand sizes. */
#define __OS "q" /* Operation Suffix */
#define __OP "r" /* Operand Prefix */
--- 2009-07-10.orig/xen/tools/symbols.c 2009-07-13 13:56:07.000000000 +0200
+++ 2009-07-10/xen/tools/symbols.c 2009-07-01 09:53:36.000000000 +0200
@@ -108,10 +108,7 @@ static int read_symbol(FILE *in, struct
else if (toupper((uint8_t)stype) == 'A')
{
/* Keep these useful absolute symbols */
- if (strcmp(sym, "__kernel_syscall_via_break") &&
- strcmp(sym, "__kernel_syscall_via_epc") &&
- strcmp(sym, "__kernel_sigtramp") &&
- strcmp(sym, "__gp"))
+ if (strcmp(sym, "__gp"))
return -1;
}
@@ -135,18 +132,9 @@ static int read_symbol(FILE *in, struct
static int symbol_valid(struct sym_entry *s)
{
/* Symbols which vary between passes. Passes 1 and 2 must have
- * identical symbol lists. The symbols_* symbols below are only added
- * after pass 1, they would be included in pass 2 when --all-symbols is
- * specified so exclude them to get a stable symbol list.
+ * identical symbol lists.
*/
static char *special_symbols[] = {
- "symbols_addresses",
- "symbols_num_syms",
- "symbols_names",
- "symbols_markers",
- "symbols_token_table",
- "symbols_token_index",
-
/* Exclude linker generated symbols which vary between passes */
"_SDA_BASE_", /* ppc */
"_SDA2_BASE_", /* ppc */
@@ -251,8 +239,9 @@ static void write_src(void)
unsigned int *markers;
char buf[KSYM_NAME_LEN+1];
+ printf("#include <xen/config.h>\n");
printf("#include <asm/types.h>\n");
- printf("#if BITS_PER_LONG == 64\n");
+ printf("#if BITS_PER_LONG == 64 && !defined(SYMBOLS_ORIGIN)\n");
printf("#define PTR .quad\n");
printf("#define ALGN .align 8\n");
printf("#else\n");
@@ -260,16 +249,21 @@ static void write_src(void)
printf("#define ALGN .align 4\n");
printf("#endif\n");
- printf(".data\n");
+ printf("\t.section .rodata, \"a\"\n");
+ printf("#ifndef SYMBOLS_ORIGIN\n");
+ printf("#define SYMBOLS_ORIGIN 0\n");
output_label("symbols_addresses");
+ printf("#else\n");
+ output_label("symbols_offsets");
+ printf("#endif\n");
for (i = 0; i < table_cnt; i++) {
- printf("\tPTR\t%#llx\n", table[i].addr);
+ printf("\tPTR\t%#llx - SYMBOLS_ORIGIN\n", table[i].addr);
}
printf("\n");
output_label("symbols_num_syms");
- printf("\tPTR\t%d\n", table_cnt);
+ printf("\t.long\t%d\n", table_cnt);
printf("\n");
/* table of offset markers, that give the offset in the compressed
stream
@@ -293,7 +287,7 @@ static void write_src(void)
output_label("symbols_markers");
for (i = 0; i < ((table_cnt + 255) >> 8); i++)
- printf("\tPTR\t%d\n", markers[i]);
+ printf("\t.long\t%d\n", markers[i]);
printf("\n");
free(markers);
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