[PARISC] Make sure use of RFI conforms to PA 2.0 and 1.1 arch docs

2.6.12-rc4-pa3 : first pass at making sure use of RFI conforms to
PA 2.0 arch pages F-4 and F-5, PA 1.1 Arch page 3-19 and 3-20.

The discussion revolves around all the rules for clearing PSW Q-bit.
The hard part is meeting all the rules for "relied upon translation".

.align directive is used to guarantee the critical sequence ends more than
8 instructions (32 bytes) from the end of page.

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

7 files changed, 146 insertions, 160 deletions

diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index be0f07f2fa58..65a82c2645a7 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -30,9 +30,9 @@
  *  - save registers to kernel stack and handle in assembly or C */
 
 
+#include <asm/psw.h>
 #include <asm/assembly.h>       /* for LDREG/STREG defines */
 #include <asm/pgtable.h>
-#include <asm/psw.h>
 #include <asm/signal.h>
 #include <asm/unistd.h>
 #include <asm/thread_info.h>
@@ -67,19 +67,22 @@
 
         /* Switch to virtual mapping, trashing only %r1 */
         .macro  virt_map
-        rsm     PSW_SM_Q,%r0
-        tovirt_r1 %r29
-        mfsp    %sr7, %r1
-        or,=    %r0,%r1,%r0 /* Only save sr7 in sr3 if sr7 != 0 */
-        mtsp    %r1, %sr3
+        /* pcxt_ssm_bug */
+        rsm     PSW_SM_I, %r0   /* barrier for "Relied upon Translation */
         mtsp    %r0, %sr4
         mtsp    %r0, %sr5
+        mfsp    %sr7, %r1
+        or,=    %r0,%r1,%r0     /* Only save sr7 in sr3 if sr7 != 0 */
+        mtsp    %r1, %sr3
+        tovirt_r1 %r29
+        load32  KERNEL_PSW, %r1
+
+        rsm     PSW_SM_QUIET,%r0        /* second "heavy weight" ctl op */
         mtsp    %r0, %sr6
         mtsp    %r0, %sr7
-        load32  KERNEL_PSW, %r1
-        mtctl   %r1, %cr22
         mtctl   %r0, %cr17      /* Clear IIASQ tail */
         mtctl   %r0, %cr17      /* Clear IIASQ head */
+        mtctl   %r1, %ipsw
         load32  4f, %r1
         mtctl   %r1, %cr18      /* Set IIAOQ tail */
         ldo     4(%r1), %r1
@@ -888,9 +891,6 @@ _switch_to_ret:
          * this way, then we will need to copy %sr3 in to PT_SR[3..7], and
          * adjust IASQ[0..1].
          *
-         * Note that the following code uses a "relied upon translation".
-         * See the parisc ACD for details. The ssm is necessary due to a
-         * PCXT bug.
          */
 
         .align 4096
@@ -985,24 +985,19 @@ intr_restore:
         rest_fp         %r1
         rest_general    %r29
 
-        /* Create a "relied upon translation" PA 2.0 Arch. F-5 */
-        ssm             0,%r0
-        nop
-        nop
-        nop
-        nop
-        nop
-        nop
-        nop
+        /* inverse of virt_map */
+        pcxt_ssm_bug
+        rsm             PSW_SM_QUIET,%r0        /* prepare for rfi */
         tophys_r1       %r29
-        rsm             (PSW_SM_Q|PSW_SM_P|PSW_SM_D|PSW_SM_I),%r0
 
         /* Restore space id's and special cr's from PT_REGS
-         * structure pointed to by r29 */
+         * structure pointed to by r29
+         */
         rest_specials   %r29
 
-        /* Important: Note that rest_stack restores r29
-         * last (we are using it)! It also restores r1 and r30. */
+        /* IMPORTANT: rest_stack restores r29 last (we are using it)!
+         * It also restores r1 and r30.
+         */
         rest_stack
 
         rfi
@@ -1153,15 +1148,17 @@ intr_save:
 
         CMPIB=,n        6,%r26,skip_save_ior
 
-        /* save_specials left ipsw value in r8 for us to test */
 
         mfctl           %cr20, %r16 /* isr */
+        nop             /* serialize mfctl on PA 2.0 to avoid 4 cycle penalty */
         mfctl           %cr21, %r17 /* ior */
 
+
 #ifdef __LP64__
         /*
          * If the interrupted code was running with W bit off (32 bit),
          * clear the b bits (bits 0 & 1) in the ior.
+         * save_specials left ipsw value in r8 for us to test.
          */
         extrd,u,*<>     %r8,PSW_W_BIT,1,%r0
         depdi           0,1,2,%r17
@@ -1487,10 +1484,10 @@ nadtlb_emulate:
         add,l           %r1,%r24,%r1           /* doesn't affect c/b bits */
 
 nadtlb_nullify:
-        mfctl           %cr22,%r8              /* Get ipsw */
+        mfctl           %ipsw,%r8
         ldil            L%PSW_N,%r9
         or              %r8,%r9,%r8            /* Set PSW_N */
-        mtctl           %r8,%cr22
+        mtctl           %r8,%ipsw
 
         rfir
         nop
diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S
index 28405edf8448..2b8738576ec2 100644
--- a/arch/parisc/kernel/head.S
+++ b/arch/parisc/kernel/head.S
@@ -224,8 +224,6 @@ stext_pdc_ret:
         mtctl   %r0,%cr12
         mtctl   %r0,%cr13
 
-        /* Prepare to RFI! Man all the cannons! */
-
         /* Initialize the global data pointer */
         loadgp
 
@@ -254,46 +252,16 @@ $is_pa20:
 $install_iva:
         mtctl           %r10,%cr14
 
-#ifdef __LP64__
-        b               aligned_rfi
+        b               aligned_rfi  /* Prepare to RFI! Man all the cannons! */
         nop
 
-        .align          256
+        .align 128
 aligned_rfi:
-        ssm             0,0
-        nop             /* 1 */
-        nop             /* 2 */
-        nop             /* 3 */
-        nop             /* 4 */
-        nop             /* 5 */
-        nop             /* 6 */
-        nop             /* 7 */
-        nop             /* 8 */
-#endif
-
-#ifdef __LP64__ /* move to psw.h? */
-#define         PSW_BITS        PSW_Q+PSW_I+PSW_D+PSW_P+PSW_R
-#else
-#define         PSW_BITS        PSW_SM_Q
-#endif
-
-$rfi:   
-        /* turn off troublesome PSW bits */
-        rsm             PSW_BITS,%r0
+        pcxt_ssm_bug
 
-        /* kernel PSW:
-         *  - no interruptions except HPMC and TOC (which are handled by PDC)
-         *  - Q bit set (IODC / PDC interruptions)
-         *  - big-endian
-         *  - virtually mapped
-         */
-        load32          KERNEL_PSW,%r10
-        mtctl           %r10,%ipsw
+        rsm             PSW_SM_QUIET,%r0        /* off troublesome PSW bits */
+        /* Don't need NOPs, have 8 compliant insn before rfi */
 
-        /* Set the space pointers for the post-RFI world
-        ** Clear the two-level IIA Space Queue, effectively setting
-        ** Kernel space.
-        */
         mtctl           %r0,%cr17       /* Clear IIASQ tail */
         mtctl           %r0,%cr17       /* Clear IIASQ head */
 
@@ -301,8 +269,11 @@ $rfi:
         mtctl           %r11,%cr18      /* IIAOQ head */
         ldo             4(%r11),%r11
         mtctl           %r11,%cr18      /* IIAOQ tail */
+
+        load32          KERNEL_PSW,%r10
+        mtctl           %r10,%ipsw
         
-        /* Jump to hyperspace */
+        /* Jump through hyperspace to Virt Mode */
         rfi
         nop
 
diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index 77e03bc0f935..71ade44c4618 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -40,8 +40,8 @@
         .level  2.0
 #endif
 
-#include <asm/assembly.h>
 #include <asm/psw.h>
+#include <asm/assembly.h>
 #include <asm/pgtable.h>
 #include <asm/cache.h>
 
@@ -62,32 +62,23 @@ flush_tlb_all_local:
          * to happen in real mode with all interruptions disabled.
          */
 
-        /*
-         * Once again, we do the rfi dance ... some day we need examine
-         * all of our uses of this type of code and see what can be
-         * consolidated.
-         */
-
-        rsm             PSW_SM_I, %r19          /* relied upon translation! PA 2.0 Arch. F-5 */
+        /* pcxt_ssm_bug - relied upon translation! PA 2.0 Arch. F-4 and F-5 */
+        rsm     PSW_SM_I, %r19          /* save I-bit state */
+        load32          PA(1f), %r1
         nop
         nop
         nop
         nop
         nop
-        nop
-        nop
-        
-        rsm             PSW_SM_Q, %r0           /* Turn off Q bit to load iia queue */
-        ldil            L%REAL_MODE_PSW, %r1
-        ldo             R%REAL_MODE_PSW(%r1), %r1
-        mtctl           %r1, %cr22
+
+        rsm             PSW_SM_Q, %r0           /* prep to load iia queue */
         mtctl           %r0, %cr17              /* Clear IIASQ tail */
         mtctl           %r0, %cr17              /* Clear IIASQ head */
-        ldil            L%PA(1f), %r1
-        ldo             R%PA(1f)(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ head */
         ldo             4(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ tail */
+        load32          REAL_MODE_PSW, %r1
+        mtctl           %r1, %ipsw
         rfi
         nop
 
@@ -178,29 +169,36 @@ fdtonemiddle:					/* Loop if LOOP = 1 */
         ADDIB>          -1, %r22, fdtoneloop    /* Outer loop count decr */
         add             %r21, %r20, %r20        /* increment space */
 
-fdtdone:
 
-        /* Switch back to virtual mode */
+fdtdone:
+        /*
+         * Switch back to virtual mode
+         */
+        /* pcxt_ssm_bug */
+        rsm             PSW_SM_I, %r0
+        load32          2f, %r1
+        nop
+        nop
+        nop
+        nop
+        nop
 
-        rsm             PSW_SM_Q, %r0           /* clear Q bit to load iia queue */
-        ldil            L%KERNEL_PSW, %r1
-        ldo             R%KERNEL_PSW(%r1), %r1
-        or              %r1, %r19, %r1          /* Set I bit if set on entry */
-        mtctl           %r1, %cr22
+        rsm             PSW_SM_Q, %r0           /* prep to load iia queue */
         mtctl           %r0, %cr17              /* Clear IIASQ tail */
         mtctl           %r0, %cr17              /* Clear IIASQ head */
-        ldil            L%(2f), %r1
-        ldo             R%(2f)(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ head */
         ldo             4(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ tail */
+        load32          KERNEL_PSW, %r1
+        or              %r1, %r19, %r1  /* I-bit to state on entry */
+        mtctl           %r1, %ipsw      /* restore I-bit (entire PSW) */
         rfi
         nop
 
 2:      bv              %r0(%r2)
         nop
-        .exit
 
+        .exit
         .procend
 
         .export flush_instruction_cache_local,code
@@ -238,7 +236,7 @@ fioneloop:					/* Loop if LOOP = 1 */
 
 fisync:
         sync
-        mtsm            %r22
+        mtsm            %r22                    /* restore I-bit */
         bv              %r0(%r2)
         nop
         .exit
@@ -281,7 +279,7 @@ fdoneloop:					/* Loop if LOOP = 1 */
 fdsync:
         syncdma
         sync
-        mtsm            %r22
+        mtsm            %r22                    /* restore I-bit */
         bv              %r0(%r2)
         nop
         .exit
@@ -988,11 +986,12 @@ flush_kernel_icache_range_asm:
         bv              %r0(%r2)
         nop
         .exit
-
         .procend
 
-        .align  128
-
+        /* align should cover use of rfi in disable_sr_hashing_asm and
+         * srdis_done.
+         */
+        .align  256
         .export disable_sr_hashing_asm,code
 
 disable_sr_hashing_asm:
@@ -1000,28 +999,26 @@ disable_sr_hashing_asm:
         .callinfo NO_CALLS
         .entry
 
-        /* Switch to real mode */
-
-        ssm             0, %r0                  /* relied upon translation! */
-        nop
-        nop
+        /*
+         * Switch to real mode
+         */
+        /* pcxt_ssm_bug */
+        rsm             PSW_SM_I, %r0
+        load32          PA(1f), %r1
         nop
         nop
         nop
         nop
         nop
-        
-        rsm             (PSW_SM_Q|PSW_SM_I), %r0 /* disable Q&I to load the iia queue */
-        ldil            L%REAL_MODE_PSW, %r1
-        ldo             R%REAL_MODE_PSW(%r1), %r1
-        mtctl           %r1, %cr22
+
+        rsm             PSW_SM_Q, %r0           /* prep to load iia queue */
         mtctl           %r0, %cr17              /* Clear IIASQ tail */
         mtctl           %r0, %cr17              /* Clear IIASQ head */
-        ldil            L%PA(1f), %r1
-        ldo             R%PA(1f)(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ head */
         ldo             4(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ tail */
+        load32          REAL_MODE_PSW, %r1
+        mtctl           %r1, %ipsw
         rfi
         nop
 
@@ -1053,27 +1050,31 @@ srdis_pcxl:
 
 srdis_pa20:
 
-        /* Disable Space Register Hashing for PCXU,PCXU+,PCXW,PCXW+ */
+        /* Disable Space Register Hashing for PCXU,PCXU+,PCXW,PCXW+,PCXW2 */
 
         .word           0x144008bc              /* mfdiag %dr2, %r28 */
         depdi           0, 54,1, %r28           /* clear DIAG_SPHASH_ENAB (bit 54) */
         .word           0x145c1840              /* mtdiag %r28, %dr2 */
 
-srdis_done:
 
+srdis_done:
         /* Switch back to virtual mode */
+        rsm             PSW_SM_I, %r0           /* prep to load iia queue */
+        load32          2f, %r1
+        nop
+        nop
+        nop
+        nop
+        nop
 
-        rsm             PSW_SM_Q, %r0           /* clear Q bit to load iia queue */
-        ldil            L%KERNEL_PSW, %r1
-        ldo             R%KERNEL_PSW(%r1), %r1
-        mtctl           %r1, %cr22
+        rsm             PSW_SM_Q, %r0           /* prep to load iia queue */
         mtctl           %r0, %cr17              /* Clear IIASQ tail */
         mtctl           %r0, %cr17              /* Clear IIASQ head */
-        ldil            L%(2f), %r1
-        ldo             R%(2f)(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ head */
         ldo             4(%r1), %r1
         mtctl           %r1, %cr18              /* IIAOQ tail */
+        load32          KERNEL_PSW, %r1
+        mtctl           %r1, %ipsw
         rfi
         nop
 
diff --git a/arch/parisc/kernel/real2.S b/arch/parisc/kernel/real2.S
index 8dd5defb7316..2310fc1b06a9 100644
--- a/arch/parisc/kernel/real2.S
+++ b/arch/parisc/kernel/real2.S
@@ -7,8 +7,8 @@
  * Copyright (C) 2000 Hewlett Packard (Paul Bame bame@puffin.external.hp.com)
  *
  */
-#include <asm/assembly.h>
 #include <asm/psw.h>
+#include <asm/assembly.h>
 
         .section        .bss
         .export real_stack
@@ -147,20 +147,17 @@ restore_control_regs:
         .text
 rfi_virt2real:
         /* switch to real mode... */
-        ssm             0,0             /* See "relied upon translation" */
-        nop                             /* PA 2.0 Arch. F-5 */
-        nop
-        nop
+        rsm             PSW_SM_I,%r0
+        load32          PA(rfi_v2r_1), %r1
         nop
         nop
         nop
         nop
         nop
         
-        rsm             (PSW_SM_Q|PSW_SM_I),%r0  /* disable Q & I bits to load iia queue */
+        rsm             PSW_SM_Q,%r0  /* disable Q & I bits to load iia queue */
         mtctl           %r0, %cr17      /* Clear IIASQ tail */
         mtctl           %r0, %cr17      /* Clear IIASQ head */
-        load32          PA(rfi_v2r_1), %r1
         mtctl           %r1, %cr18      /* IIAOQ head */
         ldo             4(%r1), %r1
         mtctl           %r1, %cr18      /* IIAOQ tail */
@@ -184,10 +181,8 @@ rfi_v2r_1:
         .text
         .align 128
 rfi_real2virt:
-        ssm             0,0             /* See "relied upon translation" */
-        nop                             /* PA 2.0 Arch. F-5 */
-        nop
-        nop
+        rsm             PSW_SM_I,%r0
+        load32          (rfi_r2v_1), %r1
         nop
         nop
         nop
@@ -197,7 +192,6 @@ rfi_real2virt:
         rsm             PSW_SM_Q,%r0    /* disable Q bit to load iia queue */
         mtctl           %r0, %cr17      /* Clear IIASQ tail */
         mtctl           %r0, %cr17      /* Clear IIASQ head */
-        load32          (rfi_r2v_1), %r1
         mtctl           %r1, %cr18      /* IIAOQ head */
         ldo             4(%r1), %r1
         mtctl           %r1, %cr18      /* IIAOQ tail */
diff --git a/include/asm-parisc/assembly.h b/include/asm-parisc/assembly.h
index 30b023411fef..b24a99e3ef9c 100644
--- a/include/asm-parisc/assembly.h
+++ b/include/asm-parisc/assembly.h
@@ -450,5 +450,30 @@
         REST_CR (%cr22, PT_PSW  (\regs))
         .endm
 
+
+        /* First step to create a "relied upon translation"
+         * See PA 2.0 Arch. page F-4 and F-5.
+         *
+         * The ssm was originally necessary due to a "PCxT bug".
+         * But someone decided it needed to be added to the architecture
+         * and this "feature" went into rev3 of PA-RISC 1.1 Arch Manual.
+         * It's been carried forward into PA 2.0 Arch as well. :^(
+         *
+         * "ssm 0,%r0" is a NOP with side effects (prefetch barrier).
+         * rsm/ssm prevents the ifetch unit from speculatively fetching
+         * instructions past this line in the code stream.
+         * PA 2.0 processor will single step all insn in the same QUAD (4 insn).
+         */
+        .macro  pcxt_ssm_bug
+        rsm     PSW_SM_I,%r0
+        nop     /* 1 */
+        nop     /* 2 */
+        nop     /* 3 */
+        nop     /* 4 */
+        nop     /* 5 */
+        nop     /* 6 */
+        nop     /* 7 */
+        .endm
+
 #endif /* __ASSEMBLY__ */
 #endif
diff --git a/include/asm-parisc/psw.h b/include/asm-parisc/psw.h
index 51323029f377..4334d6ca2add 100644
--- a/include/asm-parisc/psw.h
+++ b/include/asm-parisc/psw.h
@@ -1,4 +1,7 @@
 #ifndef _PARISC_PSW_H
+
+#include <linux/config.h>
+
 #define PSW_I   0x00000001
 #define PSW_D   0x00000002
 #define PSW_P   0x00000004
@@ -9,6 +12,16 @@
 #define PSW_G   0x00000040      /* PA1.x only */
 #define PSW_O   0x00000080      /* PA2.0 only */
 
+/* ssm/rsm instructions number PSW_W and PSW_E differently */
+#define PSW_SM_I        PSW_I   /* Enable External Interrupts */
+#define PSW_SM_D        PSW_D
+#define PSW_SM_P        PSW_P
+#define PSW_SM_Q        PSW_Q   /* Enable Interrupt State Collection */
+#define PSW_SM_R        PSW_R   /* Enable Recover Counter Trap */
+#define PSW_SM_W        0x200   /* PA2.0 only : Enable Wide Mode */
+
+#define PSW_SM_QUIET    PSW_SM_R+PSW_SM_Q+PSW_SM_P+PSW_SM_D+PSW_SM_I
+
 #define PSW_CB  0x0000ff00
 
 #define PSW_M   0x00010000
@@ -30,33 +43,21 @@
 #define PSW_Z   0x40000000      /* PA1.x only */
 #define PSW_Y   0x80000000      /* PA1.x only */
 
-#ifdef __LP64__
-#define PSW_HI_CB 0x000000ff    /* PA2.0 only */
+#ifdef CONFIG_64BIT
+#  define PSW_HI_CB 0x000000ff    /* PA2.0 only */
 #endif
 
-/* PSW bits to be used with ssm/rsm */
-#define PSW_SM_I        0x1
-#define PSW_SM_D        0x2
-#define PSW_SM_P        0x4
-#define PSW_SM_Q        0x8
-#define PSW_SM_R        0x10
-#define PSW_SM_F        0x20
-#define PSW_SM_G        0x40
-#define PSW_SM_O        0x80
-#define PSW_SM_E        0x100
-#define PSW_SM_W        0x200
-
-#ifdef __LP64__
-#  define USER_PSW      (PSW_C | PSW_Q | PSW_P | PSW_D | PSW_I)
-#  define KERNEL_PSW    (PSW_W | PSW_C | PSW_Q | PSW_P | PSW_D)
-#  define REAL_MODE_PSW (PSW_W | PSW_Q)
-#  define USER_PSW_MASK (PSW_W | PSW_T | PSW_N | PSW_X | PSW_B | PSW_V | PSW_CB)
-#  define USER_PSW_HI_MASK (PSW_HI_CB)
-#else
-#  define USER_PSW      (PSW_C | PSW_Q | PSW_P | PSW_D | PSW_I)
-#  define KERNEL_PSW    (PSW_C | PSW_Q | PSW_P | PSW_D)
-#  define REAL_MODE_PSW (PSW_Q)
-#  define USER_PSW_MASK (PSW_T | PSW_N | PSW_X | PSW_B | PSW_V | PSW_CB)
+#ifdef CONFIG_64BIT
+#  define USER_PSW_HI_MASK      PSW_HI_CB
+#  define WIDE_PSW              PSW_W
+#else 
+#  define WIDE_PSW              0
 #endif
 
+/* Used when setting up for rfi */
+#define KERNEL_PSW    (WIDE_PSW | PSW_C | PSW_Q | PSW_P | PSW_D)
+#define REAL_MODE_PSW (WIDE_PSW | PSW_Q)
+#define USER_PSW_MASK (WIDE_PSW | PSW_T | PSW_N | PSW_X | PSW_B | PSW_V | PSW_CB)
+#define USER_PSW      (PSW_C | PSW_Q | PSW_P | PSW_D | PSW_I)
+
 #endif
diff --git a/include/asm-parisc/tlbflush.h b/include/asm-parisc/tlbflush.h
index eb27b78930e8..efbb2d8625b1 100644
--- a/include/asm-parisc/tlbflush.h
+++ b/include/asm-parisc/tlbflush.h
@@ -64,29 +64,26 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
 {
         unsigned long npages;
 
-        
         npages = ((end - (start & PAGE_MASK)) + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
-        if (npages >= 512)  /* XXX arbitrary, should be tuned */
+        if (npages >= 512)  /* 2MB of space: arbitrary, should be tuned */
                 flush_tlb_all();
         else {
 
                 mtsp(vma->vm_mm->context,1);
+                purge_tlb_start();
                 if (split_tlb) {
-                        purge_tlb_start();
                         while (npages--) {
                                 pdtlb(start);
                                 pitlb(start);
                                 start += PAGE_SIZE;
                         }
-                        purge_tlb_end();
                 } else {
-                        purge_tlb_start();
                         while (npages--) {
                                 pdtlb(start);
                                 start += PAGE_SIZE;
                         }
-                        purge_tlb_end();
                 }
+                purge_tlb_end();
         }
 }