[patch 12/12] syslets: x86_64: add syslet/threadlet support

From: Ingo Molnar
Date: Wed Feb 28 2007 - 16:52:40 EST

From: Ingo Molnar <mingo@xxxxxxx>

add the arch specific bits of syslet/threadlet support to x86_64.

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86_64/Kconfig | 4 ++
arch/x86_64/ia32/ia32entry.S | 20 ++++++++++-
arch/x86_64/kernel/entry.S | 72 ++++++++++++++++++++++++++++++++++++++++-
arch/x86_64/kernel/process.c | 11 ++++++
include/asm-x86_64/processor.h | 16 +++++++++
include/asm-x86_64/system.h | 12 ++++++
include/asm-x86_64/unistd.h | 29 +++++++++++++++-
7 files changed, 160 insertions(+), 4 deletions(-)

Index: linux/arch/x86_64/Kconfig
===================================================================
--- linux.orig/arch/x86_64/Kconfig
+++ linux/arch/x86_64/Kconfig
@@ -36,6 +36,10 @@ config ZONE_DMA32
bool
default y

+config ASYNC_SUPPORT
+ bool
+ default y
+
config LOCKDEP_SUPPORT
bool
default y
Index: linux/arch/x86_64/ia32/ia32entry.S
===================================================================
--- linux.orig/arch/x86_64/ia32/ia32entry.S
+++ linux/arch/x86_64/ia32/ia32entry.S
@@ -368,6 +368,14 @@ quiet_ni_syscall:
PTREGSCALL stub32_vfork, sys_vfork, %rdi
PTREGSCALL stub32_iopl, sys_iopl, %rsi
PTREGSCALL stub32_rt_sigsuspend, sys_rt_sigsuspend, %rdx
+ /*
+ * sys_async_thread() and sys_async_exec() both take 2 parameters,
+ * none of which is ptregs - but the syscalls rely on being able to
+ * modify ptregs. So we put ptregs into the 3rd parameter - so it's
+ * unused and it also does not mess up the first 2 parameters:
+ */
+ PTREGSCALL stub32_compat_async_exec, compat_sys_async_exec, %rdx
+ PTREGSCALL stub32_compat_async_thread, sys_async_thread, %rdx

ENTRY(ia32_ptregs_common)
popq %r11
@@ -394,6 +402,9 @@ END(ia32_ptregs_common)

.section .rodata,"a"
.align 8
+.globl compat_sys_call_table
+compat_sys_call_table:
+.globl ia32_sys_call_table
ia32_sys_call_table:
.quad sys_restart_syscall
.quad sys_exit
@@ -714,9 +725,16 @@ ia32_sys_call_table:
.quad compat_sys_get_robust_list
.quad sys_splice
.quad sys_sync_file_range
- .quad sys_tee
+ .quad sys_tee /* 315 */
.quad compat_sys_vmsplice
.quad compat_sys_move_pages
.quad sys_getcpu
.quad sys_epoll_pwait
+ .quad stub32_compat_async_exec /* 320 */
+ .quad sys_async_wait
+ .quad sys_umem_add
+ .quad stub32_compat_async_thread
+ .quad sys_threadlet_on
+ .quad sys_threadlet_off /* 325 */
+.globl ia32_syscall_end
ia32_syscall_end:
Index: linux/arch/x86_64/kernel/entry.S
===================================================================
--- linux.orig/arch/x86_64/kernel/entry.S
+++ linux/arch/x86_64/kernel/entry.S
@@ -410,6 +410,14 @@ END(\label)
PTREGSCALL stub_rt_sigsuspend, sys_rt_sigsuspend, %rdx
PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
PTREGSCALL stub_iopl, sys_iopl, %rsi
+ /*
+ * sys_async_thread() and sys_async_exec() both take 2 parameters,
+ * none of which is ptregs - but the syscalls rely on being able to
+ * modify ptregs. So we put ptregs into the 3rd parameter - so it's
+ * unused and it also does not mess up the first 2 parameters:
+ */
+ PTREGSCALL stub_async_thread, sys_async_thread, %rdx
+ PTREGSCALL stub_async_exec, sys_async_exec, %rdx

ENTRY(ptregscall_common)
popq %r11
@@ -430,7 +438,7 @@ ENTRY(ptregscall_common)
ret
CFI_ENDPROC
END(ptregscall_common)
-
+
ENTRY(stub_execve)
CFI_STARTPROC
popq %r11
@@ -990,6 +998,68 @@ child_rip:
ENDPROC(child_rip)

/*
+ * Create an async kernel thread.
+ *
+ * C extern interface:
+ * extern long create_async_thread(int (*fn)(void *), void * arg, unsigned long flags)
+ *
+ * asm input arguments:
+ * rdi: fn, rsi: arg, rdx: flags
+ */
+ENTRY(create_async_thread)
+ CFI_STARTPROC
+ FAKE_STACK_FRAME $async_child_rip
+ SAVE_ALL
+
+ # rdi: flags, rsi: usp, rdx: will be &pt_regs
+ movq %rdx,%rdi
+ movq $-1, %rsi
+ movq %rsp, %rdx
+
+ xorl %r8d,%r8d
+ xorl %r9d,%r9d
+
+ # clone now
+ call do_fork
+ movq %rax,RAX(%rsp)
+ xorl %edi,%edi
+
+ /*
+ * It isn't worth to check for reschedule here,
+ * so internally to the x86_64 port you can rely on kernel_thread()
+ * not to reschedule the child before returning, this avoids the need
+ * of hacks for example to fork off the per-CPU idle tasks.
+ * [Hopefully no generic code relies on the reschedule -AK]
+ */
+ RESTORE_ALL
+ UNFAKE_STACK_FRAME
+ ret
+ CFI_ENDPROC
+ENDPROC(async_kernel_thread)
+
+async_child_rip:
+ CFI_STARTPROC
+
+ movq %rdi, %rax
+ movq %rsi, %rdi
+ call *%rax
+
+ /*
+ * Fix up the PDA - we might return with sysexit:
+ */
+ RESTORE_TOP_OF_STACK %r11
+
+ /*
+ * return to user-space:
+ */
+ movq %rax, RAX(%rsp)
+ RESTORE_REST
+ jmp int_ret_from_sys_call
+
+ CFI_ENDPROC
+ENDPROC(async_child_rip)
+
+/*
* execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
*
* C extern interface:
Index: linux/arch/x86_64/kernel/process.c
===================================================================
--- linux.orig/arch/x86_64/kernel/process.c
+++ linux/arch/x86_64/kernel/process.c
@@ -418,6 +418,17 @@ void release_thread(struct task_struct *
}
}

+/*
+ * Move user-space context from one kernel thread to another.
+ * Callers must make sure that neither task is running user context
+ * at the moment:
+ */
+void
+move_user_context(struct task_struct *new_task, struct task_struct *old_task)
+{
+ *task_pt_regs(new_task) = *task_pt_regs(old_task);
+}
+
static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
{
struct user_desc ud = {
Index: linux/include/asm-x86_64/processor.h
===================================================================
--- linux.orig/include/asm-x86_64/processor.h
+++ linux/include/asm-x86_64/processor.h
@@ -322,6 +322,11 @@ extern void prepare_to_copy(struct task_
extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);

/*
+ * create an async thread:
+ */
+extern long create_async_thread(long (*fn)(void *), void * arg, unsigned long flags);
+
+/*
* Return saved PC of a blocked thread.
* What is this good for? it will be always the scheduler or ret_from_fork.
*/
@@ -332,6 +337,17 @@ extern unsigned long get_wchan(struct ta
#define KSTK_EIP(tsk) (task_pt_regs(tsk)->rip)
#define KSTK_ESP(tsk) -1 /* sorry. doesn't work for syscall. */

+/*
+ * Register access methods for async syscall support.
+ *
+ * Note, task_stack_reg() must not be an lvalue, hence this macro:
+ */
+#define task_stack_reg(t) \
+ ({ unsigned long __rsp = task_pt_regs(t)->rsp; __rsp; })
+#define set_task_stack_reg(t, new_stack) \
+ do { task_pt_regs(t)->rsp = (new_stack); } while (0)
+#define task_ip_reg(t) task_pt_regs(t)->rip
+#define task_ret_reg(t) task_pt_regs(t)->rax

struct microcode_header {
unsigned int hdrver;
Index: linux/include/asm-x86_64/system.h
===================================================================
--- linux.orig/include/asm-x86_64/system.h
+++ linux/include/asm-x86_64/system.h
@@ -20,6 +20,8 @@
#define __EXTRA_CLOBBER \
,"rcx","rbx","rdx","r8","r9","r10","r11","r12","r13","r14","r15"

+struct task_struct;
+
/* Save restore flags to clear handle leaking NT */
#define switch_to(prev,next,last) \
asm volatile(SAVE_CONTEXT \
@@ -42,7 +44,15 @@
[thread_info] "i" (offsetof(struct task_struct, thread_info)), \
[pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent)) \
: "memory", "cc" __EXTRA_CLOBBER)
-
+
+
+/*
+ * Move user-space context from one kernel thread to another.
+ * This includes registers and FPU state for now:
+ */
+extern void
+move_user_context(struct task_struct *new_task, struct task_struct *old_task);
+
extern void load_gs_index(unsigned);

/*
Index: linux/include/asm-x86_64/unistd.h
===================================================================
--- linux.orig/include/asm-x86_64/unistd.h
+++ linux/include/asm-x86_64/unistd.h
@@ -619,8 +619,21 @@ __SYSCALL(__NR_sync_file_range, sys_sync
__SYSCALL(__NR_vmsplice, sys_vmsplice)
#define __NR_move_pages 279
__SYSCALL(__NR_move_pages, sys_move_pages)
+#define __NR_async_exec 280
+__SYSCALL(__NR_async_exec, stub_async_exec)
+#define __NR_async_wait 281
+__SYSCALL(__NR_async_wait, sys_async_wait)
+#define __NR_umem_add 282
+__SYSCALL(__NR_umem_add, sys_umem_add)
+#define __NR_async_thread 283
+__SYSCALL(__NR_async_thread, stub_async_thread)
+#define __NR_threadlet_on 284
+__SYSCALL(__NR_threadlet_on, sys_threadlet_on)
+#define __NR_threadlet_off 285
+__SYSCALL(__NR_threadlet_off, sys_threadlet_off)

-#define __NR_syscall_max __NR_move_pages
+#define __NR_syscall_max __NR_threadlet_off
+#define NR_syscalls __NR_syscall_max

#ifndef __NO_STUBS
#define __ARCH_WANT_OLD_READDIR
@@ -654,6 +667,20 @@ __SYSCALL(__NR_move_pages, sys_move_page
#include <linux/types.h>
#include <asm/ptrace.h>

+typedef asmlinkage long (*syscall_fn_t)(long, long, long, long, long, long);
+
+extern syscall_fn_t sys_call_table[NR_syscalls];
+
+#ifdef CONFIG_COMPAT
+
+extern syscall_fn_t compat_sys_call_table[];
+extern syscall_fn_t ia32_syscall_end;
+extern syscall_fn_t ia32_sys_call_table;
+
+#define compat_NR_syscalls (&ia32_syscall_end - compat_sys_call_table)
+
+#endif
+
asmlinkage long sys_iopl(unsigned int level, struct pt_regs *regs);
asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on);
struct sigaction;
-
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