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List: linux-ia64
Subject: [PATCH 13/15] ia64/pv_ops: move down __kernel_syscall_via_epc.
From: Isaku Yamahata <yamahata () valinux ! co ! jp>
Date: 2008-12-22 5:50:20
Message-ID: 1229925022-31365-14-git-send-email-yamahata () valinux ! co ! jp
[Download RAW message or body]
Move down __kernel_syscall_via_epc to the end of the page.
We want to paravirtualize only __kernel_syscall_via_epc because
it includes privileged instructions. Its paravirtualization increases
its symbols size.
On the other hand, each paravirtualized gate must have e symbols of
same value and size to native's because the page is mapped to GATE_ADDR
and GATE_ADDR + PERCPU_PAGE_SIZE and vmlinux is linked to those symbols.
Later to have the same symbol size, we pads NOPs at the end of
__kernel_syscall_via_epc. Move it after other functions to keep
symbols of other functions have same values and sizes.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
---
arch/ia64/kernel/gate.S | 162 +++++++++++++++++++++++-----------------------
1 files changed, 81 insertions(+), 81 deletions(-)
diff --git a/arch/ia64/kernel/gate.S b/arch/ia64/kernel/gate.S
index 74b1ccc..c957228 100644
--- a/arch/ia64/kernel/gate.S
+++ b/arch/ia64/kernel/gate.S
@@ -48,87 +48,6 @@ GLOBAL_ENTRY(__kernel_syscall_via_break)
}
END(__kernel_syscall_via_break)
-/*
- * On entry:
- * r11 = saved ar.pfs
- * r15 = system call #
- * b0 = saved return address
- * b6 = return address
- * On exit:
- * r11 = saved ar.pfs
- * r15 = system call #
- * b0 = saved return address
- * all other "scratch" registers: undefined
- * all "preserved" registers: same as on entry
- */
-
-GLOBAL_ENTRY(__kernel_syscall_via_epc)
- .prologue
- .altrp b6
- .body
-{
- /*
- * Note: the kernel cannot assume that the first two instructions in this
- * bundle get executed. The remaining code must be safe even if
- * they do not get executed.
- */
- adds r17=-1024,r15 // A
- mov r10=0 // A default to successful syscall execution
- epc // B causes split-issue
-}
- ;;
- rsm psr.be | psr.i // M2 (5 cyc to srlz.d)
- LOAD_FSYSCALL_TABLE(r14) // X
- ;;
- mov r16=IA64_KR(CURRENT) // M2 (12 cyc)
- shladd r18=r17,3,r14 // A
- mov r19=NR_syscalls-1 // A
- ;;
- lfetch [r18] // M0|1
- mov r29=psr // M2 (12 cyc)
- // If r17 is a NaT, p6 will be zero
- cmp.geu p6,p7=r19,r17 // A (sysnr > 0 && sysnr < 1024+NR_syscalls)?
- ;;
- mov r21=ar.fpsr // M2 (12 cyc)
- tnat.nz p10,p9=r15 // I0
- mov.i r26=ar.pfs // I0 (would stall anyhow due to srlz.d...)
- ;;
- srlz.d // M0 (forces split-issue) ensure PSR.BE==0
-(p6) ld8 r18=[r18] // M0|1
- nop.i 0
- ;;
- nop.m 0
-(p6) tbit.z.unc p8,p0=r18,0 // I0 (dual-issues with "mov b7=r18"!)
- nop.i 0
- ;;
-(p8) ssm psr.i
-(p6) mov b7=r18 // I0
-(p8) br.dptk.many b7 // B
-
- mov r27=ar.rsc // M2 (12 cyc)
-/*
- * brl.cond doesn't work as intended because the linker would convert this branch
- * into a branch to a PLT. Perhaps there will be a way to avoid this with some
- * future version of the linker. In the meantime, we just use an indirect branch
- * instead.
- */
-#ifdef CONFIG_ITANIUM
-(p6) add r14=-8,r14 // r14 <- addr of fsys_bubble_down entry
- ;;
-(p6) ld8 r14=[r14] // r14 <- fsys_bubble_down
- ;;
-(p6) mov b7=r14
-(p6) br.sptk.many b7
-#else
- BRL_COND_FSYS_BUBBLE_DOWN(p6)
-#endif
- ssm psr.i
- mov r10=-1
-(p10) mov r8=EINVAL
-(p9) mov r8=ENOSYS
- FSYS_RETURN
-END(__kernel_syscall_via_epc)
-
# define ARG0_OFF (16 + IA64_SIGFRAME_ARG0_OFFSET)
# define ARG1_OFF (16 + IA64_SIGFRAME_ARG1_OFFSET)
# define ARG2_OFF (16 + IA64_SIGFRAME_ARG2_OFFSET)
@@ -374,3 +293,84 @@ restore_rbs:
// invala not necessary as that will happen when returning to user-mode
br.cond.sptk back_from_restore_rbs
END(__kernel_sigtramp)
+
+/*
+ * On entry:
+ * r11 = saved ar.pfs
+ * r15 = system call #
+ * b0 = saved return address
+ * b6 = return address
+ * On exit:
+ * r11 = saved ar.pfs
+ * r15 = system call #
+ * b0 = saved return address
+ * all other "scratch" registers: undefined
+ * all "preserved" registers: same as on entry
+ */
+
+GLOBAL_ENTRY(__kernel_syscall_via_epc)
+ .prologue
+ .altrp b6
+ .body
+{
+ /*
+ * Note: the kernel cannot assume that the first two instructions in this
+ * bundle get executed. The remaining code must be safe even if
+ * they do not get executed.
+ */
+ adds r17=-1024,r15 // A
+ mov r10=0 // A default to successful syscall execution
+ epc // B causes split-issue
+}
+ ;;
+ rsm psr.be | psr.i // M2 (5 cyc to srlz.d)
+ LOAD_FSYSCALL_TABLE(r14) // X
+ ;;
+ mov r16=IA64_KR(CURRENT) // M2 (12 cyc)
+ shladd r18=r17,3,r14 // A
+ mov r19=NR_syscalls-1 // A
+ ;;
+ lfetch [r18] // M0|1
+ mov r29=psr // M2 (12 cyc)
+ // If r17 is a NaT, p6 will be zero
+ cmp.geu p6,p7=r19,r17 // A (sysnr > 0 && sysnr < 1024+NR_syscalls)?
+ ;;
+ mov r21=ar.fpsr // M2 (12 cyc)
+ tnat.nz p10,p9=r15 // I0
+ mov.i r26=ar.pfs // I0 (would stall anyhow due to srlz.d...)
+ ;;
+ srlz.d // M0 (forces split-issue) ensure PSR.BE==0
+(p6) ld8 r18=[r18] // M0|1
+ nop.i 0
+ ;;
+ nop.m 0
+(p6) tbit.z.unc p8,p0=r18,0 // I0 (dual-issues with "mov b7=r18"!)
+ nop.i 0
+ ;;
+(p8) ssm psr.i
+(p6) mov b7=r18 // I0
+(p8) br.dptk.many b7 // B
+
+ mov r27=ar.rsc // M2 (12 cyc)
+/*
+ * brl.cond doesn't work as intended because the linker would convert this branch
+ * into a branch to a PLT. Perhaps there will be a way to avoid this with some
+ * future version of the linker. In the meantime, we just use an indirect branch
+ * instead.
+ */
+#ifdef CONFIG_ITANIUM
+(p6) add r14=-8,r14 // r14 <- addr of fsys_bubble_down entry
+ ;;
+(p6) ld8 r14=[r14] // r14 <- fsys_bubble_down
+ ;;
+(p6) mov b7=r14
+(p6) br.sptk.many b7
+#else
+ BRL_COND_FSYS_BUBBLE_DOWN(p6)
+#endif
+ ssm psr.i
+ mov r10=-1
+(p10) mov r8=EINVAL
+(p9) mov r8=ENOSYS
+ FSYS_RETURN
+END(__kernel_syscall_via_epc)
--
1.6.0.2
--
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