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linux_dsm_epyc7002/arch/blackfin/kernel/process.c
Bernd Schmidt bc41bb1165 Blackfin arch: fix bug libstdc++ calling writev with an iovec containing { NULL, 0 } fails on Blackfin 
Fix a problem reported in the forums - libstdc++ can call writev with an
iovec containing { NULL, 0 }, which works fine on i686-linux, but fails on
Blackfin.  Fixed by allowing size 0 transfers to/from userspace regardless
of the address.

Signed-off-by: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
2007-10-10 17:54:19 +08:00

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/*
* File: arch/blackfin/kernel/process.c
* Based on:
* Author:
*
* Created:
* Description: Blackfin architecture-dependent process handling.
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <linux/unistd.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/uaccess.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <asm/blackfin.h>
#include <asm/fixed_code.h>
#define LED_ON 0
#define LED_OFF 1
asmlinkage void ret_from_fork(void);
/* Points to the SDRAM backup memory for the stack that is currently in
* L1 scratchpad memory.
*/
void *current_l1_stack_save;
/* The number of tasks currently using a L1 stack area. The SRAM is
* allocated/deallocated whenever this changes from/to zero.
*/
int nr_l1stack_tasks;
/* Start and length of the area in L1 scratchpad memory which we've allocated
* for process stacks.
*/
void *l1_stack_base;
unsigned long l1_stack_len;
/*
* Powermanagement idle function, if any..
*/
void (*pm_idle)(void) = NULL;
EXPORT_SYMBOL(pm_idle);
void (*pm_power_off)(void) = NULL;
EXPORT_SYMBOL(pm_power_off);
/*
* We are using a different LED from the one used to indicate timer interrupt.
*/
#if defined(CONFIG_BFIN_IDLE_LED)
static inline void leds_switch(int flag)
{
unsigned short tmp = 0;
tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
SSYNC();
if (flag == LED_ON)
tmp &= ~CONFIG_BFIN_IDLE_LED_PIN; /* light on */
else
tmp |= CONFIG_BFIN_IDLE_LED_PIN; /* light off */
bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
SSYNC();
}
#else
static inline void leds_switch(int flag)
{
}
#endif
/*
* The idle loop on BFIN
*/
#ifdef CONFIG_IDLE_L1
void default_idle(void)__attribute__((l1_text));
void cpu_idle(void)__attribute__((l1_text));
#endif
void default_idle(void)
{
while (!need_resched()) {
leds_switch(LED_OFF);
local_irq_disable();
if (likely(!need_resched()))
idle_with_irq_disabled();
local_irq_enable();
leds_switch(LED_ON);
}
}
void (*idle)(void) = default_idle;
/*
* The idle thread. There's no useful work to be
* done, so just try to conserve power and have a
* low exit latency (ie sit in a loop waiting for
* somebody to say that they'd like to reschedule)
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
idle();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
void show_regs(struct pt_regs *regs)
{
printk(KERN_NOTICE "\n");
printk(KERN_NOTICE
"PC: %08lu Status: %04lu SysStatus: %04lu RETS: %08lu\n",
regs->pc, regs->astat, regs->seqstat, regs->rets);
printk(KERN_NOTICE
"A0.x: %08lx A0.w: %08lx A1.x: %08lx A1.w: %08lx\n",
regs->a0x, regs->a0w, regs->a1x, regs->a1w);
printk(KERN_NOTICE "P0: %08lx P1: %08lx P2: %08lx P3: %08lx\n",
regs->p0, regs->p1, regs->p2, regs->p3);
printk(KERN_NOTICE "P4: %08lx P5: %08lx\n", regs->p4, regs->p5);
printk(KERN_NOTICE "R0: %08lx R1: %08lx R2: %08lx R3: %08lx\n",
regs->r0, regs->r1, regs->r2, regs->r3);
printk(KERN_NOTICE "R4: %08lx R5: %08lx R6: %08lx R7: %08lx\n",
regs->r4, regs->r5, regs->r6, regs->r7);
if (!regs->ipend)
printk(KERN_NOTICE "USP: %08lx\n", rdusp());
}
/* Fill in the fpu structure for a core dump. */
int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
{
return 1;
}
/*
* This gets run with P1 containing the
* function to call, and R1 containing
* the "args". Note P0 is clobbered on the way here.
*/
void kernel_thread_helper(void);
__asm__(".section .text\n"
".align 4\n"
"_kernel_thread_helper:\n\t"
"\tsp += -12;\n\t"
"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
/*
* Create a kernel thread.
*/
pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
regs.r1 = (unsigned long)arg;
regs.p1 = (unsigned long)fn;
regs.pc = (unsigned long)kernel_thread_helper;
regs.orig_p0 = -1;
/* Set bit 2 to tell ret_from_fork we should be returning to kernel
mode. */
regs.ipend = 0x8002;
__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
NULL);
}
void flush_thread(void)
{
}
asmlinkage int bfin_vfork(struct pt_regs *regs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
NULL);
}
asmlinkage int bfin_clone(struct pt_regs *regs)
{
unsigned long clone_flags;
unsigned long newsp;
/* syscall2 puts clone_flags in r0 and usp in r1 */
clone_flags = regs->r0;
newsp = regs->r1;
if (!newsp)
newsp = rdusp();
else
newsp -= 12;
return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
}
int
copy_thread(int nr, unsigned long clone_flags,
unsigned long usp, unsigned long topstk,
struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs;
childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
*childregs = *regs;
childregs->r0 = 0;
p->thread.usp = usp;
p->thread.ksp = (unsigned long)childregs;
p->thread.pc = (unsigned long)ret_from_fork;
return 0;
}
/*
* fill in the user structure for a core dump..
*/
void dump_thread(struct pt_regs *regs, struct user *dump)
{
dump->magic = CMAGIC;
dump->start_code = 0;
dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
dump->u_tsize = ((unsigned long)current->mm->end_code) >> PAGE_SHIFT;
dump->u_dsize = ((unsigned long)(current->mm->brk +
(PAGE_SIZE - 1))) >> PAGE_SHIFT;
dump->u_dsize -= dump->u_tsize;
dump->u_ssize = 0;
if (dump->start_stack < TASK_SIZE)
dump->u_ssize =
((unsigned long)(TASK_SIZE -
dump->start_stack)) >> PAGE_SHIFT;
dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
dump->regs.r0 = regs->r0;
dump->regs.r1 = regs->r1;
dump->regs.r2 = regs->r2;
dump->regs.r3 = regs->r3;
dump->regs.r4 = regs->r4;
dump->regs.r5 = regs->r5;
dump->regs.r6 = regs->r6;
dump->regs.r7 = regs->r7;
dump->regs.p0 = regs->p0;
dump->regs.p1 = regs->p1;
dump->regs.p2 = regs->p2;
dump->regs.p3 = regs->p3;
dump->regs.p4 = regs->p4;
dump->regs.p5 = regs->p5;
dump->regs.orig_p0 = regs->orig_p0;
dump->regs.a0w = regs->a0w;
dump->regs.a1w = regs->a1w;
dump->regs.a0x = regs->a0x;
dump->regs.a1x = regs->a1x;
dump->regs.rets = regs->rets;
dump->regs.astat = regs->astat;
dump->regs.pc = regs->pc;
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys_execve(char *name, char **argv, char **envp)
{
int error;
char *filename;
struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
lock_kernel();
filename = getname(name);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = do_execve(filename, argv, envp, regs);
putname(filename);
out:
unlock_kernel();
return error;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)p;
fp = p->thread.usp;
do {
if (fp < stack_page + sizeof(struct thread_info) ||
fp >= 8184 + stack_page)
return 0;
pc = ((unsigned long *)fp)[1];
if (!in_sched_functions(pc))
return pc;
fp = *(unsigned long *)fp;
}
while (count++ < 16);
return 0;
}
void finish_atomic_sections (struct pt_regs *regs)
{
if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
return;
switch (regs->pc) {
case ATOMIC_XCHG32 + 2:
put_user(regs->r1, (int *)regs->p0);
regs->pc += 2;
break;
case ATOMIC_CAS32 + 2:
case ATOMIC_CAS32 + 4:
if (regs->r0 == regs->r1)
put_user(regs->r2, (int *)regs->p0);
regs->pc = ATOMIC_CAS32 + 8;
break;
case ATOMIC_CAS32 + 6:
put_user(regs->r2, (int *)regs->p0);
regs->pc += 2;
break;
case ATOMIC_ADD32 + 2:
regs->r0 = regs->r1 + regs->r0;
/* fall through */
case ATOMIC_ADD32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_ADD32 + 6;
break;
case ATOMIC_SUB32 + 2:
regs->r0 = regs->r1 - regs->r0;
/* fall through */
case ATOMIC_SUB32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_SUB32 + 6;
break;
case ATOMIC_IOR32 + 2:
regs->r0 = regs->r1 | regs->r0;
/* fall through */
case ATOMIC_IOR32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_IOR32 + 6;
break;
case ATOMIC_AND32 + 2:
regs->r0 = regs->r1 & regs->r0;
/* fall through */
case ATOMIC_AND32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_AND32 + 6;
break;
case ATOMIC_XOR32 + 2:
regs->r0 = regs->r1 ^ regs->r0;
/* fall through */
case ATOMIC_XOR32 + 4:
put_user(regs->r0, (int *)regs->p0);
regs->pc = ATOMIC_XOR32 + 6;
break;
}
}
#if defined(CONFIG_ACCESS_CHECK)
int _access_ok(unsigned long addr, unsigned long size)
{
if (size == 0)
return 1;
if (addr > (addr + size))
return 0;
if (segment_eq(get_fs(), KERNEL_DS))
return 1;
#ifdef CONFIG_MTD_UCLINUX
if (addr >= memory_start && (addr + size) <= memory_end)
return 1;
if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
return 1;
#else
if (addr >= memory_start && (addr + size) <= physical_mem_end)
return 1;
#endif
if (addr >= (unsigned long)__init_begin &&
addr + size <= (unsigned long)__init_end)
return 1;
if (addr >= L1_SCRATCH_START
&& addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
return 1;
#if L1_CODE_LENGTH != 0
if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
&& addr + size <= L1_CODE_START + L1_CODE_LENGTH)
return 1;
#endif
#if L1_DATA_A_LENGTH != 0
if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
&& addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
return 1;
#endif
#if L1_DATA_B_LENGTH != 0
if (addr >= L1_DATA_B_START
&& addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
return 1;
#endif
return 0;
}
EXPORT_SYMBOL(_access_ok);
#endif /* CONFIG_ACCESS_CHECK */
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