kernel-fxtec-pro1x/include/asm-sparc64/cpudata.h
David S. Miller 86b818687d [SPARC64]: Fix race in LOAD_PER_CPU_BASE()
Since we use %g5 itself as a temporary, it can get clobbered
if we take an interrupt mid-stream and thus cause end up with
the final %g5 value too early as a result of rtrap processing.

Set %g5 at the very end, atomically, to avoid this problem.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:11:29 -08:00

125 lines
3.5 KiB
C

/* cpudata.h: Per-cpu parameters.
*
* Copyright (C) 2003, 2005, 2006 David S. Miller (davem@davemloft.net)
*/
#ifndef _SPARC64_CPUDATA_H
#define _SPARC64_CPUDATA_H
#ifndef __ASSEMBLY__
#include <linux/percpu.h>
#include <linux/threads.h>
typedef struct {
/* Dcache line 1 */
unsigned int __softirq_pending; /* must be 1st, see rtrap.S */
unsigned int multiplier;
unsigned int counter;
unsigned int idle_volume;
unsigned long clock_tick; /* %tick's per second */
unsigned long udelay_val;
/* Dcache line 2, rarely used */
unsigned int dcache_size;
unsigned int dcache_line_size;
unsigned int icache_size;
unsigned int icache_line_size;
unsigned int ecache_size;
unsigned int ecache_line_size;
unsigned int __pad3;
unsigned int __pad4;
} cpuinfo_sparc;
DECLARE_PER_CPU(cpuinfo_sparc, __cpu_data);
#define cpu_data(__cpu) per_cpu(__cpu_data, (__cpu))
#define local_cpu_data() __get_cpu_var(__cpu_data)
/* Trap handling code needs to get at a few critical values upon
* trap entry and to process TSB misses. These cannot be in the
* per_cpu() area as we really need to lock them into the TLB and
* thus make them part of the main kernel image. As a result we
* try to make this as small as possible.
*
* This is padded out and aligned to 64-bytes to avoid false sharing
* on SMP.
*/
/* If you modify the size of this structure, please update
* TRAP_BLOCK_SZ_SHIFT below.
*/
struct thread_info;
struct trap_per_cpu {
/* D-cache line 1 */
struct thread_info *thread;
unsigned long pgd_paddr;
unsigned long __pad1[2];
/* D-cache line 2 */
unsigned long __pad2[4];
} __attribute__((aligned(64)));
extern struct trap_per_cpu trap_block[NR_CPUS];
extern void init_cur_cpu_trap(void);
extern void per_cpu_patch(void);
extern void setup_tba(void);
#endif /* !(__ASSEMBLY__) */
#define TRAP_PER_CPU_THREAD 0x00
#define TRAP_PER_CPU_PGD_PADDR 0x08
#define TRAP_BLOCK_SZ_SHIFT 6
/* Clobbers %g1, loads %g6 with local processor's cpuid */
#define __GET_CPUID \
ba,pt %xcc, __get_cpu_id; \
rd %pc, %g1;
/* Clobbers %g1, current address space PGD phys address into %g7. */
#define TRAP_LOAD_PGD_PHYS \
__GET_CPUID \
sllx %g6, TRAP_BLOCK_SZ_SHIFT, %g6; \
sethi %hi(trap_block), %g7; \
or %g7, %lo(trap_block), %g7; \
add %g7, %g6, %g7; \
ldx [%g7 + TRAP_PER_CPU_PGD_PADDR], %g7;
/* Clobbers %g1, loads local processor's IRQ work area into %g6. */
#define TRAP_LOAD_IRQ_WORK \
__GET_CPUID \
sethi %hi(__irq_work), %g1; \
sllx %g6, 6, %g6; \
or %g1, %lo(__irq_work), %g1; \
add %g1, %g6, %g6;
/* Clobbers %g1, loads %g6 with current thread info pointer. */
#define TRAP_LOAD_THREAD_REG \
__GET_CPUID \
sllx %g6, TRAP_BLOCK_SZ_SHIFT, %g6; \
sethi %hi(trap_block), %g1; \
or %g1, %lo(trap_block), %g1; \
ldx [%g1 + %g6], %g6;
/* Given the current thread info pointer in %g6, load the per-cpu
* area base of the current processor into %g5. REG1, REG2, and REG3 are
* clobbered.
*
* You absolutely cannot use %g5 as a temporary in this code. The
* reason is that traps can happen during execution, and return from
* trap will load the fully resolved %g5 per-cpu base. This can corrupt
* the calculations done by the macro mid-stream.
*/
#ifdef CONFIG_SMP
#define LOAD_PER_CPU_BASE(REG1, REG2, REG3) \
ldub [%g6 + TI_CPU], REG1; \
sethi %hi(__per_cpu_shift), REG3; \
sethi %hi(__per_cpu_base), REG2; \
ldx [REG3 + %lo(__per_cpu_shift)], REG3; \
ldx [REG2 + %lo(__per_cpu_base)], REG2; \
sllx REG1, REG3, REG3; \
add REG3, REG2, %g5;
#else
#define LOAD_PER_CPU_BASE(REG1, REG2, REG3)
#endif
#endif /* _SPARC64_CPUDATA_H */