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authorPavel Emelyanov <xemul@openvz.org>2008-03-28 14:27:00 -0700
committerTony Luck <tony.luck@intel.com>2008-04-09 10:33:36 -0700
commit96ded9dadde397a9e372a650534a9ffbba97194a (patch)
tree9aaa92034e87218d3ab7ba7e33fad0661899a0ad /arch/ia64
parentd167cb85150bd473a27df71e3116a9cc0008f5dd (diff)
[IA64] fix getpid and set_tid_address fast system calls for pid namespaces
The sys_getpid() and sys_set_tid_address() behavior changed from return current->tgid to struct pid *pid; pid = current->pids[PIDTYPE_PID].pid; return pid->numbers[pid->level].nr; But the fast system calls on ia64 still operate the old way. Patch them appropriately to let ia64 work with pid namespaces. Besides, this is one more step in deprecating of pid and tgid on task_struct. The fsys_getppid() is to be patched as well, but its logic is much more complex now, so I will make it later. One thing I'm not 100% sure is the trick with the IA64_UPID_SHIFT. On order to access the pid->level's element of an array I have to perform the following calculations pid + sizeof(struct upid) * pid->level The problem is that ia64 can only multiply float point registers, while all the offsets I have in code are in rXX ones. Fortunately, the sizeof(struct upid) is 32 bytes on ia64 (and is very unlikely to ever change), so the calculations get simpler: pid + pid->level << 5 So, I introduce the IA64_UPID_SHIFT and use the shl instruction. I also looked at how gcc compiles the similar place and found that it makes it with shift as well. Is this OK to do so? Tested with ski emulator with 2.6.24 kernel, but fits 2.6.25-rc4 and 2.6.25-rc4-mm1 as well. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: David Mosberger-Tang <davidm@hpl.hp.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/kernel/asm-offsets.c7
-rw-r--r--arch/ia64/kernel/fsys.S34
2 files changed, 37 insertions, 4 deletions
diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c
index 0aebc6f79e9..f7bc40dee43 100644
--- a/arch/ia64/kernel/asm-offsets.c
+++ b/arch/ia64/kernel/asm-offsets.c
@@ -7,6 +7,7 @@
#define ASM_OFFSETS_C 1
#include <linux/sched.h>
+#include <linux/pid.h>
#include <linux/clocksource.h>
#include <asm-ia64/processor.h>
@@ -34,6 +35,9 @@ void foo(void)
DEFINE(SIGFRAME_SIZE, sizeof (struct sigframe));
DEFINE(UNW_FRAME_INFO_SIZE, sizeof (struct unw_frame_info));
+ BUILD_BUG_ON(sizeof(struct upid) != 32);
+ DEFINE(IA64_UPID_SHIFT, 5);
+
BLANK();
DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
@@ -45,6 +49,9 @@ void foo(void)
DEFINE(IA64_TASK_BLOCKED_OFFSET,offsetof (struct task_struct, blocked));
DEFINE(IA64_TASK_CLEAR_CHILD_TID_OFFSET,offsetof (struct task_struct, clear_child_tid));
DEFINE(IA64_TASK_GROUP_LEADER_OFFSET, offsetof (struct task_struct, group_leader));
+ DEFINE(IA64_TASK_TGIDLINK_OFFSET, offsetof (struct task_struct, pids[PIDTYPE_PID].pid));
+ DEFINE(IA64_PID_LEVEL_OFFSET, offsetof (struct pid, level));
+ DEFINE(IA64_PID_UPID_OFFSET, offsetof (struct pid, numbers[0]));
DEFINE(IA64_TASK_PENDING_OFFSET,offsetof (struct task_struct, pending));
DEFINE(IA64_TASK_PID_OFFSET, offsetof (struct task_struct, pid));
DEFINE(IA64_TASK_REAL_PARENT_OFFSET, offsetof (struct task_struct, real_parent));
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S
index 44841971f07..3f570e6fcd9 100644
--- a/arch/ia64/kernel/fsys.S
+++ b/arch/ia64/kernel/fsys.S
@@ -61,13 +61,29 @@ ENTRY(fsys_getpid)
.prologue
.altrp b6
.body
+ add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16
+ ;;
+ ld8 r17=[r17] // r17 = current->group_leader
add r9=TI_FLAGS+IA64_TASK_SIZE,r16
;;
ld4 r9=[r9]
- add r8=IA64_TASK_TGID_OFFSET,r16
+ add r17=IA64_TASK_TGIDLINK_OFFSET,r17
;;
and r9=TIF_ALLWORK_MASK,r9
- ld4 r8=[r8] // r8 = current->tgid
+ ld8 r17=[r17] // r17 = current->group_leader->pids[PIDTYPE_PID].pid
+ ;;
+ add r8=IA64_PID_LEVEL_OFFSET,r17
+ ;;
+ ld4 r8=[r8] // r8 = pid->level
+ add r17=IA64_PID_UPID_OFFSET,r17 // r17 = &pid->numbers[0]
+ ;;
+ shl r8=r8,IA64_UPID_SHIFT
+ ;;
+ add r17=r17,r8 // r17 = &pid->numbers[pid->level]
+ ;;
+ ld4 r8=[r17] // r8 = pid->numbers[pid->level].nr
+ ;;
+ mov r17=0
;;
cmp.ne p8,p0=0,r9
(p8) br.spnt.many fsys_fallback_syscall
@@ -126,15 +142,25 @@ ENTRY(fsys_set_tid_address)
.altrp b6
.body
add r9=TI_FLAGS+IA64_TASK_SIZE,r16
+ add r17=IA64_TASK_TGIDLINK_OFFSET,r16
;;
ld4 r9=[r9]
tnat.z p6,p7=r32 // check argument register for being NaT
+ ld8 r17=[r17] // r17 = current->pids[PIDTYPE_PID].pid
;;
and r9=TIF_ALLWORK_MASK,r9
- add r8=IA64_TASK_PID_OFFSET,r16
+ add r8=IA64_PID_LEVEL_OFFSET,r17
add r18=IA64_TASK_CLEAR_CHILD_TID_OFFSET,r16
;;
- ld4 r8=[r8]
+ ld4 r8=[r8] // r8 = pid->level
+ add r17=IA64_PID_UPID_OFFSET,r17 // r17 = &pid->numbers[0]
+ ;;
+ shl r8=r8,IA64_UPID_SHIFT
+ ;;
+ add r17=r17,r8 // r17 = &pid->numbers[pid->level]
+ ;;
+ ld4 r8=[r17] // r8 = pid->numbers[pid->level].nr
+ ;;
cmp.ne p8,p0=0,r9
mov r17=-1
;;