xtensa: complete ptrace handling of register windows

Compute WindowBase and WindowMask registers correctly on ptrace calls.
Work done earlier by Maxim, Christian and Marc.

Signed-off-by: Marc Gauthier <marc@tensilica.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

1 files changed, 20 insertions, 13 deletions

diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c
index 61fb2e9e9035..a8b0d5795571 100644
--- a/arch/xtensa/kernel/ptrace.c
+++ b/arch/xtensa/kernel/ptrace.c
@@ -53,9 +53,8 @@ int ptrace_getregs(struct task_struct *child, void __user *uregs)
 {
         struct pt_regs *regs = task_pt_regs(child);
         xtensa_gregset_t __user *gregset = uregs;
-        unsigned long wm = regs->wmask;
         unsigned long wb = regs->windowbase;
-        int live, i;
+        int i;
 
         if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
                 return -EIO;
@@ -68,12 +67,9 @@ int ptrace_getregs(struct task_struct *child, void __user *uregs)
         __put_user(regs->windowstart, &gregset->windowstart);
         __put_user(regs->windowbase, &gregset->windowbase);
 
-        live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
-
-        for (i = 0; i < live; i++)
-                __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
-        for (i = XCHAL_NUM_AREGS - (wm >> 4) * 4; i < XCHAL_NUM_AREGS; i++)
-                __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
+        for (i = 0; i < XCHAL_NUM_AREGS; i++)
+                __put_user(regs->areg[i],
+                                gregset->a + ((wb * 4 + i) % XCHAL_NUM_AREGS));
 
         return 0;
 }
@@ -84,7 +80,7 @@ int ptrace_setregs(struct task_struct *child, void __user *uregs)
         xtensa_gregset_t *gregset = uregs;
         const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
         unsigned long ps;
-        unsigned long wb;
+        unsigned long wb, ws;
 
         if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
                 return -EIO;
@@ -94,7 +90,7 @@ int ptrace_setregs(struct task_struct *child, void __user *uregs)
         __get_user(regs->lbeg, &gregset->lbeg);
         __get_user(regs->lend, &gregset->lend);
         __get_user(regs->lcount, &gregset->lcount);
-        __get_user(regs->windowstart, &gregset->windowstart);
+        __get_user(ws, &gregset->windowstart);
         __get_user(wb, &gregset->windowbase);
 
         regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);
@@ -102,13 +98,24 @@ int ptrace_setregs(struct task_struct *child, void __user *uregs)
         if (wb >= XCHAL_NUM_AREGS / 4)
                 return -EFAULT;
 
-        regs->windowbase = wb;
+        if (wb != regs->windowbase || ws != regs->windowstart) {
+                unsigned long rotws, wmask;
+
+                rotws = (((ws | (ws << WSBITS)) >> wb) &
+                                ((1 << WSBITS) - 1)) & ~1;
+                wmask = ((rotws ? WSBITS + 1 - ffs(rotws) : 0) << 4) |
+                        (rotws & 0xF) | 1;
+                regs->windowbase = wb;
+                regs->windowstart = ws;
+                regs->wmask = wmask;
+        }
 
         if (wb != 0 &&  __copy_from_user(regs->areg + XCHAL_NUM_AREGS - wb * 4,
-                                         gregset->a, wb * 16))
+                                gregset->a, wb * 16))
                 return -EFAULT;
 
-        if (__copy_from_user(regs->areg, gregset->a + wb*4, (WSBITS-wb) * 16))
+        if (__copy_from_user(regs->areg, gregset->a + wb * 4,
+                                (WSBITS - wb) * 16))
                 return -EFAULT;
 
         return 0;