ia64/pv_ops: move down __kernel_syscall_via_epc.

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>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/kernel/gate.S b/arch/ia64/kernel/gate.S
index 74b1ccc..c957228 100644 (file)
--- 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)