From ef62a2d81f73d9cddef14bc3d9097a57010d551c Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 31 Mar 2017 10:37:44 +0100 Subject: metag/usercopy: Drop unused macros Metag's lib/usercopy.c has a bunch of copy_from_user macros for larger copies between 5 and 16 bytes which are completely unused. Before fixing zeroing lets drop these macros so there is less to fix. Signed-off-by: James Hogan Cc: Al Viro Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/lib/usercopy.c | 113 ---------------------------------------------- 1 file changed, 113 deletions(-) diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index b3ebfe9c8e88..b4eb1f17069f 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -651,119 +651,6 @@ EXPORT_SYMBOL(__copy_user); #define __asm_copy_from_user_4(to, from, ret) \ __asm_copy_from_user_4x_cont(to, from, ret, "", "", "") -#define __asm_copy_from_user_5(to, from, ret) \ - __asm_copy_from_user_4x_cont(to, from, ret, \ - " GETB D1Ar1,[%1++]\n" \ - "4: SETB [%0++],D1Ar1\n", \ - "5: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ - " .long 4b,5b\n") - -#define __asm_copy_from_user_6x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ - __asm_copy_from_user_4x_cont(to, from, ret, \ - " GETW D1Ar1,[%1++]\n" \ - "4: SETW [%0++],D1Ar1\n" COPY, \ - "5: ADD %2,%2,#2\n" \ - " SETW [%0++],D1Ar1\n" FIXUP, \ - " .long 4b,5b\n" TENTRY) - -#define __asm_copy_from_user_6(to, from, ret) \ - __asm_copy_from_user_6x_cont(to, from, ret, "", "", "") - -#define __asm_copy_from_user_7(to, from, ret) \ - __asm_copy_from_user_6x_cont(to, from, ret, \ - " GETB D1Ar1,[%1++]\n" \ - "6: SETB [%0++],D1Ar1\n", \ - "7: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ - " .long 6b,7b\n") - -#define __asm_copy_from_user_8x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ - __asm_copy_from_user_4x_cont(to, from, ret, \ - " GETD D1Ar1,[%1++]\n" \ - "4: SETD [%0++],D1Ar1\n" COPY, \ - "5: ADD %2,%2,#4\n" \ - " SETD [%0++],D1Ar1\n" FIXUP, \ - " .long 4b,5b\n" TENTRY) - -#define __asm_copy_from_user_8(to, from, ret) \ - __asm_copy_from_user_8x_cont(to, from, ret, "", "", "") - -#define __asm_copy_from_user_9(to, from, ret) \ - __asm_copy_from_user_8x_cont(to, from, ret, \ - " GETB D1Ar1,[%1++]\n" \ - "6: SETB [%0++],D1Ar1\n", \ - "7: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ - " .long 6b,7b\n") - -#define __asm_copy_from_user_10x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ - __asm_copy_from_user_8x_cont(to, from, ret, \ - " GETW D1Ar1,[%1++]\n" \ - "6: SETW [%0++],D1Ar1\n" COPY, \ - "7: ADD %2,%2,#2\n" \ - " SETW [%0++],D1Ar1\n" FIXUP, \ - " .long 6b,7b\n" TENTRY) - -#define __asm_copy_from_user_10(to, from, ret) \ - __asm_copy_from_user_10x_cont(to, from, ret, "", "", "") - -#define __asm_copy_from_user_11(to, from, ret) \ - __asm_copy_from_user_10x_cont(to, from, ret, \ - " GETB D1Ar1,[%1++]\n" \ - "8: SETB [%0++],D1Ar1\n", \ - "9: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ - " .long 8b,9b\n") - -#define __asm_copy_from_user_12x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ - __asm_copy_from_user_8x_cont(to, from, ret, \ - " GETD D1Ar1,[%1++]\n" \ - "6: SETD [%0++],D1Ar1\n" COPY, \ - "7: ADD %2,%2,#4\n" \ - " SETD [%0++],D1Ar1\n" FIXUP, \ - " .long 6b,7b\n" TENTRY) - -#define __asm_copy_from_user_12(to, from, ret) \ - __asm_copy_from_user_12x_cont(to, from, ret, "", "", "") - -#define __asm_copy_from_user_13(to, from, ret) \ - __asm_copy_from_user_12x_cont(to, from, ret, \ - " GETB D1Ar1,[%1++]\n" \ - "8: SETB [%0++],D1Ar1\n", \ - "9: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ - " .long 8b,9b\n") - -#define __asm_copy_from_user_14x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ - __asm_copy_from_user_12x_cont(to, from, ret, \ - " GETW D1Ar1,[%1++]\n" \ - "8: SETW [%0++],D1Ar1\n" COPY, \ - "9: ADD %2,%2,#2\n" \ - " SETW [%0++],D1Ar1\n" FIXUP, \ - " .long 8b,9b\n" TENTRY) - -#define __asm_copy_from_user_14(to, from, ret) \ - __asm_copy_from_user_14x_cont(to, from, ret, "", "", "") - -#define __asm_copy_from_user_15(to, from, ret) \ - __asm_copy_from_user_14x_cont(to, from, ret, \ - " GETB D1Ar1,[%1++]\n" \ - "10: SETB [%0++],D1Ar1\n", \ - "11: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ - " .long 10b,11b\n") - -#define __asm_copy_from_user_16x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ - __asm_copy_from_user_12x_cont(to, from, ret, \ - " GETD D1Ar1,[%1++]\n" \ - "8: SETD [%0++],D1Ar1\n" COPY, \ - "9: ADD %2,%2,#4\n" \ - " SETD [%0++],D1Ar1\n" FIXUP, \ - " .long 8b,9b\n" TENTRY) - -#define __asm_copy_from_user_16(to, from, ret) \ - __asm_copy_from_user_16x_cont(to, from, ret, "", "", "") #define __asm_copy_from_user_8x64(to, from, ret) \ asm volatile ( \ -- cgit v1.2.3 From 2257211942bbbf6c798ab70b487d7e62f7835a1a Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 31 Mar 2017 11:23:18 +0100 Subject: metag/usercopy: Fix alignment error checking Fix the error checking of the alignment adjustment code in raw_copy_from_user(), which mistakenly considers it safe to skip the error check when aligning the source buffer on a 2 or 4 byte boundary. If the destination buffer was unaligned it may have started to copy using byte or word accesses, which could well be at the start of a new (valid) source page. This would result in it appearing to have copied 1 or 2 bytes at the end of the first (invalid) page rather than none at all. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/lib/usercopy.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index b4eb1f17069f..a6ced9691ddb 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -717,6 +717,8 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, if ((unsigned long) src & 1) { __asm_copy_from_user_1(dst, src, retn); n--; + if (retn) + goto copy_exception_bytes; } if ((unsigned long) dst & 1) { /* Worst case - byte copy */ @@ -730,6 +732,8 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, if (((unsigned long) src & 2) && n >= 2) { __asm_copy_from_user_2(dst, src, retn); n -= 2; + if (retn) + goto copy_exception_bytes; } if ((unsigned long) dst & 2) { /* Second worst case - word copy */ @@ -741,12 +745,6 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, } } - /* We only need one check after the unalignment-adjustments, - because if both adjustments were done, either both or - neither reference had an exception. */ - if (retn != 0) - goto copy_exception_bytes; - #ifdef USE_RAPF /* 64 bit copy loop */ if (!(((unsigned long) src | (unsigned long) dst) & 7)) { -- cgit v1.2.3 From fb8ea062a8f2e85256e13f55696c5c5f0dfdcc8b Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 31 Mar 2017 13:35:01 +0100 Subject: metag/usercopy: Add early abort to copy_to_user When copying to userland on Meta, if any faults are encountered immediately abort the copy instead of continuing on and repeatedly faulting, and worse potentially copying further bytes successfully to subsequent valid pages. Fixes: 373cd784d0fc ("metag: Memory handling") Reported-by: Al Viro Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/lib/usercopy.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index a6ced9691ddb..714d8562aa20 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -538,23 +538,31 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, if ((unsigned long) src & 1) { __asm_copy_to_user_1(dst, src, retn); n--; + if (retn) + return retn + n; } if ((unsigned long) dst & 1) { /* Worst case - byte copy */ while (n > 0) { __asm_copy_to_user_1(dst, src, retn); n--; + if (retn) + return retn + n; } } if (((unsigned long) src & 2) && n >= 2) { __asm_copy_to_user_2(dst, src, retn); n -= 2; + if (retn) + return retn + n; } if ((unsigned long) dst & 2) { /* Second worst case - word copy */ while (n >= 2) { __asm_copy_to_user_2(dst, src, retn); n -= 2; + if (retn) + return retn + n; } } @@ -569,6 +577,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, while (n >= 8) { __asm_copy_to_user_8x64(dst, src, retn); n -= 8; + if (retn) + return retn + n; } } if (n >= RAPF_MIN_BUF_SIZE) { @@ -581,6 +591,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, while (n >= 8) { __asm_copy_to_user_8x64(dst, src, retn); n -= 8; + if (retn) + return retn + n; } } #endif @@ -588,11 +600,15 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, while (n >= 16) { __asm_copy_to_user_16(dst, src, retn); n -= 16; + if (retn) + return retn + n; } while (n >= 4) { __asm_copy_to_user_4(dst, src, retn); n -= 4; + if (retn) + return retn + n; } switch (n) { @@ -609,6 +625,10 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, break; } + /* + * If we get here, retn correctly reflects the number of failing + * bytes. + */ return retn; } EXPORT_SYMBOL(__copy_user); -- cgit v1.2.3 From 563ddc1076109f2b3f88e6d355eab7b6fd4662cb Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 31 Mar 2017 11:14:02 +0100 Subject: metag/usercopy: Zero rest of buffer from copy_from_user Currently we try to zero the destination for a failed read from userland in fixup code in the usercopy.c macros. The rest of the destination buffer is then zeroed from __copy_user_zeroing(), which is used for both copy_from_user() and __copy_from_user(). Unfortunately we fail to zero in the fixup code as D1Ar1 is set to 0 before the fixup code entry labels, and __copy_from_user() shouldn't even be zeroing the rest of the buffer. Move the zeroing out into copy_from_user() and rename __copy_user_zeroing() to raw_copy_from_user() since it no longer does any zeroing. This also conveniently matches the name needed for RAW_COPY_USER support in a later patch. Fixes: 373cd784d0fc ("metag: Memory handling") Reported-by: Al Viro Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/include/asm/uaccess.h | 15 ++++++----- arch/metag/lib/usercopy.c | 57 +++++++++++++--------------------------- 2 files changed, 26 insertions(+), 46 deletions(-) diff --git a/arch/metag/include/asm/uaccess.h b/arch/metag/include/asm/uaccess.h index 273e61225c27..07238b39638c 100644 --- a/arch/metag/include/asm/uaccess.h +++ b/arch/metag/include/asm/uaccess.h @@ -197,20 +197,21 @@ extern long __must_check strnlen_user(const char __user *src, long count); #define strlen_user(str) strnlen_user(str, 32767) -extern unsigned long __must_check __copy_user_zeroing(void *to, - const void __user *from, - unsigned long n); +extern unsigned long raw_copy_from_user(void *to, const void __user *from, + unsigned long n); static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n) { + unsigned long res = n; if (likely(access_ok(VERIFY_READ, from, n))) - return __copy_user_zeroing(to, from, n); - memset(to, 0, n); - return n; + res = raw_copy_from_user(to, from, n); + if (unlikely(res)) + memset(to + (n - res), 0, res); + return res; } -#define __copy_from_user(to, from, n) __copy_user_zeroing(to, from, n) +#define __copy_from_user(to, from, n) raw_copy_from_user(to, from, n) #define __copy_from_user_inatomic __copy_from_user extern unsigned long __must_check __copy_user(void __user *to, diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index 714d8562aa20..e1d553872fd7 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -29,7 +29,6 @@ COPY \ "1:\n" \ " .section .fixup,\"ax\"\n" \ - " MOV D1Ar1,#0\n" \ FIXUP \ " MOVT D1Ar1,#HI(1b)\n" \ " JUMP D1Ar1,#LO(1b)\n" \ @@ -637,16 +636,14 @@ EXPORT_SYMBOL(__copy_user); __asm_copy_user_cont(to, from, ret, \ " GETB D1Ar1,[%1++]\n" \ "2: SETB [%0++],D1Ar1\n", \ - "3: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ + "3: ADD %2,%2,#1\n", \ " .long 2b,3b\n") #define __asm_copy_from_user_2x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ __asm_copy_user_cont(to, from, ret, \ " GETW D1Ar1,[%1++]\n" \ "2: SETW [%0++],D1Ar1\n" COPY, \ - "3: ADD %2,%2,#2\n" \ - " SETW [%0++],D1Ar1\n" FIXUP, \ + "3: ADD %2,%2,#2\n" FIXUP, \ " .long 2b,3b\n" TENTRY) #define __asm_copy_from_user_2(to, from, ret) \ @@ -656,32 +653,26 @@ EXPORT_SYMBOL(__copy_user); __asm_copy_from_user_2x_cont(to, from, ret, \ " GETB D1Ar1,[%1++]\n" \ "4: SETB [%0++],D1Ar1\n", \ - "5: ADD %2,%2,#1\n" \ - " SETB [%0++],D1Ar1\n", \ + "5: ADD %2,%2,#1\n", \ " .long 4b,5b\n") #define __asm_copy_from_user_4x_cont(to, from, ret, COPY, FIXUP, TENTRY) \ __asm_copy_user_cont(to, from, ret, \ " GETD D1Ar1,[%1++]\n" \ "2: SETD [%0++],D1Ar1\n" COPY, \ - "3: ADD %2,%2,#4\n" \ - " SETD [%0++],D1Ar1\n" FIXUP, \ + "3: ADD %2,%2,#4\n" FIXUP, \ " .long 2b,3b\n" TENTRY) #define __asm_copy_from_user_4(to, from, ret) \ __asm_copy_from_user_4x_cont(to, from, ret, "", "", "") - #define __asm_copy_from_user_8x64(to, from, ret) \ asm volatile ( \ " GETL D0Ar2,D1Ar1,[%1++]\n" \ "2: SETL [%0++],D0Ar2,D1Ar1\n" \ "1:\n" \ " .section .fixup,\"ax\"\n" \ - " MOV D1Ar1,#0\n" \ - " MOV D0Ar2,#0\n" \ "3: ADD %2,%2,#8\n" \ - " SETL [%0++],D0Ar2,D1Ar1\n" \ " MOVT D0Ar2,#HI(1b)\n" \ " JUMP D0Ar2,#LO(1b)\n" \ " .previous\n" \ @@ -721,11 +712,12 @@ EXPORT_SYMBOL(__copy_user); "SUB %1, %1, #4\n") -/* Copy from user to kernel, zeroing the bytes that were inaccessible in - userland. The return-value is the number of bytes that were - inaccessible. */ -unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, - unsigned long n) +/* + * Copy from user to kernel. The return-value is the number of bytes that were + * inaccessible. + */ +unsigned long raw_copy_from_user(void *pdst, const void __user *psrc, + unsigned long n) { register char *dst asm ("A0.2") = pdst; register const char __user *src asm ("A1.2") = psrc; @@ -738,7 +730,7 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, __asm_copy_from_user_1(dst, src, retn); n--; if (retn) - goto copy_exception_bytes; + return retn + n; } if ((unsigned long) dst & 1) { /* Worst case - byte copy */ @@ -746,14 +738,14 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, __asm_copy_from_user_1(dst, src, retn); n--; if (retn) - goto copy_exception_bytes; + return retn + n; } } if (((unsigned long) src & 2) && n >= 2) { __asm_copy_from_user_2(dst, src, retn); n -= 2; if (retn) - goto copy_exception_bytes; + return retn + n; } if ((unsigned long) dst & 2) { /* Second worst case - word copy */ @@ -761,7 +753,7 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, __asm_copy_from_user_2(dst, src, retn); n -= 2; if (retn) - goto copy_exception_bytes; + return retn + n; } } @@ -777,7 +769,7 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, __asm_copy_from_user_8x64(dst, src, retn); n -= 8; if (retn) - goto copy_exception_bytes; + return retn + n; } } @@ -793,7 +785,7 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, __asm_copy_from_user_8x64(dst, src, retn); n -= 8; if (retn) - goto copy_exception_bytes; + return retn + n; } } #endif @@ -803,7 +795,7 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, n -= 4; if (retn) - goto copy_exception_bytes; + return retn + n; } /* If we get here, there were no memory read faults. */ @@ -829,21 +821,8 @@ unsigned long __copy_user_zeroing(void *pdst, const void __user *psrc, /* If we get here, retn correctly reflects the number of failing bytes. */ return retn; - - copy_exception_bytes: - /* We already have "retn" bytes cleared, and need to clear the - remaining "n" bytes. A non-optimized simple byte-for-byte in-line - memset is preferred here, since this isn't speed-critical code and - we'd rather have this a leaf-function than calling memset. */ - { - char *endp; - for (endp = dst + n; dst < endp; dst++) - *dst = 0; - } - - return retn + n; } -EXPORT_SYMBOL(__copy_user_zeroing); +EXPORT_SYMBOL(raw_copy_from_user); #define __asm_clear_8x64(to, ret) \ asm volatile ( \ -- cgit v1.2.3 From fd40eee1290ad7add7aa665e3ce6b0f9fe9734b4 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 4 Apr 2017 11:43:26 +0100 Subject: metag/usercopy: Set flags before ADDZ The fixup code for the copy_to_user rapf loops reads TXStatus.LSM_STEP to decide how far to rewind the source pointer. There is a special case for the last execution of an MGETL/MGETD, since it leaves LSM_STEP=0 even though the number of MGETLs/MGETDs attempted was 4. This uses ADDZ which is conditional upon the Z condition flag, but the AND instruction which masked the TXStatus.LSM_STEP field didn't set the condition flags based on the result. Fix that now by using ANDS which does set the flags, and also marking the condition codes as clobbered by the inline assembly. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/lib/usercopy.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index e1d553872fd7..4422928a1746 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -315,7 +315,7 @@ " .previous\n" \ : "=r" (to), "=r" (from), "=r" (ret), "=d" (n) \ : "0" (to), "1" (from), "2" (ret), "3" (n) \ - : "D1Ar1", "D0Ar2", "memory") + : "D1Ar1", "D0Ar2", "cc", "memory") /* rewind 'to' and 'from' pointers when a fault occurs * @@ -341,7 +341,7 @@ #define __asm_copy_to_user_64bit_rapf_loop(to, from, ret, n, id)\ __asm_copy_user_64bit_rapf_loop(to, from, ret, n, id, \ "LSR D0Ar2, D0Ar2, #8\n" \ - "AND D0Ar2, D0Ar2, #0x7\n" \ + "ANDS D0Ar2, D0Ar2, #0x7\n" \ "ADDZ D0Ar2, D0Ar2, #4\n" \ "SUB D0Ar2, D0Ar2, #1\n" \ "MOV D1Ar1, #4\n" \ @@ -486,7 +486,7 @@ " .previous\n" \ : "=r" (to), "=r" (from), "=r" (ret), "=d" (n) \ : "0" (to), "1" (from), "2" (ret), "3" (n) \ - : "D1Ar1", "D0Ar2", "memory") + : "D1Ar1", "D0Ar2", "cc", "memory") /* rewind 'to' and 'from' pointers when a fault occurs * @@ -512,7 +512,7 @@ #define __asm_copy_to_user_32bit_rapf_loop(to, from, ret, n, id)\ __asm_copy_user_32bit_rapf_loop(to, from, ret, n, id, \ "LSR D0Ar2, D0Ar2, #8\n" \ - "AND D0Ar2, D0Ar2, #0x7\n" \ + "ANDS D0Ar2, D0Ar2, #0x7\n" \ "ADDZ D0Ar2, D0Ar2, #4\n" \ "SUB D0Ar2, D0Ar2, #1\n" \ "MOV D1Ar1, #4\n" \ -- cgit v1.2.3 From 2c0b1df88b987a12d95ea1d6beaf01894f3cc725 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Mon, 3 Apr 2017 17:41:40 +0100 Subject: metag/usercopy: Fix src fixup in from user rapf loops The fixup code to rewind the source pointer in __asm_copy_from_user_{32,64}bit_rapf_loop() always rewound the source by a single unit (4 or 8 bytes), however this is insufficient if the fault didn't occur on the first load in the loop, as the source pointer will have been incremented but nothing will have been stored until all 4 register [pairs] are loaded. Read the LSM_STEP field of TXSTATUS (which is already loaded into a register), a bit like the copy_to_user versions, to determine how many iterations of MGET[DL] have taken place, all of which need rewinding. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/lib/usercopy.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-) diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index 4422928a1746..e09c95ba028c 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -687,29 +687,49 @@ EXPORT_SYMBOL(__copy_user); * * Rationale: * A fault occurs while reading from user buffer, which is the - * source. Since the fault is at a single address, we only - * need to rewind by 8 bytes. + * source. * Since we don't write to kernel buffer until we read first, * the kernel buffer is at the right state and needn't be - * corrected. + * corrected, but the source must be rewound to the beginning of + * the block, which is LSM_STEP*8 bytes. + * LSM_STEP is bits 10:8 in TXSTATUS which is already read + * and stored in D0Ar2 + * + * NOTE: If a fault occurs at the last operation in M{G,S}ETL + * LSM_STEP will be 0. ie: we do 4 writes in our case, if + * a fault happens at the 4th write, LSM_STEP will be 0 + * instead of 4. The code copes with that. */ #define __asm_copy_from_user_64bit_rapf_loop(to, from, ret, n, id) \ __asm_copy_user_64bit_rapf_loop(to, from, ret, n, id, \ - "SUB %1, %1, #8\n") + "LSR D0Ar2, D0Ar2, #5\n" \ + "ANDS D0Ar2, D0Ar2, #0x38\n" \ + "ADDZ D0Ar2, D0Ar2, #32\n" \ + "SUB %1, %1, D0Ar2\n") /* rewind 'from' pointer when a fault occurs * * Rationale: * A fault occurs while reading from user buffer, which is the - * source. Since the fault is at a single address, we only - * need to rewind by 4 bytes. + * source. * Since we don't write to kernel buffer until we read first, * the kernel buffer is at the right state and needn't be - * corrected. + * corrected, but the source must be rewound to the beginning of + * the block, which is LSM_STEP*4 bytes. + * LSM_STEP is bits 10:8 in TXSTATUS which is already read + * and stored in D0Ar2 + * + * NOTE: If a fault occurs at the last operation in M{G,S}ETL + * LSM_STEP will be 0. ie: we do 4 writes in our case, if + * a fault happens at the 4th write, LSM_STEP will be 0 + * instead of 4. The code copes with that. */ #define __asm_copy_from_user_32bit_rapf_loop(to, from, ret, n, id) \ __asm_copy_user_32bit_rapf_loop(to, from, ret, n, id, \ - "SUB %1, %1, #4\n") + "LSR D0Ar2, D0Ar2, #6\n" \ + "ANDS D0Ar2, D0Ar2, #0x1c\n" \ + "ADDZ D0Ar2, D0Ar2, #16\n" \ + "SUB %1, %1, D0Ar2\n") /* -- cgit v1.2.3 From b884a190afcecdbef34ca508ea5ee88bb7c77861 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 4 Apr 2017 08:51:34 +0100 Subject: metag/usercopy: Add missing fixups The rapf copy loops in the Meta usercopy code is missing some extable entries for HTP cores with unaligned access checking enabled, where faults occur on the instruction immediately after the faulting access. Add the fixup labels and extable entries for these cases so that corner case user copy failures don't cause kernel crashes. Fixes: 373cd784d0fc ("metag: Memory handling") Signed-off-by: James Hogan Cc: linux-metag@vger.kernel.org Cc: stable@vger.kernel.org --- arch/metag/lib/usercopy.c | 72 +++++++++++++++++++++++++++++++---------------- 1 file changed, 48 insertions(+), 24 deletions(-) diff --git a/arch/metag/lib/usercopy.c b/arch/metag/lib/usercopy.c index e09c95ba028c..2792fc621088 100644 --- a/arch/metag/lib/usercopy.c +++ b/arch/metag/lib/usercopy.c @@ -259,27 +259,31 @@ "MGETL D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ "22:\n" \ "MSETL [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ - "SUB %3, %3, #32\n" \ "23:\n" \ - "MGETL D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ + "SUB %3, %3, #32\n" \ "24:\n" \ + "MGETL D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ + "25:\n" \ "MSETL [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "26:\n" \ "SUB %3, %3, #32\n" \ "DCACHE [%1+#-64], D0Ar6\n" \ "BR $Lloop"id"\n" \ \ "MOV RAPF, %1\n" \ - "25:\n" \ + "27:\n" \ "MGETL D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "26:\n" \ + "28:\n" \ "MSETL [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "29:\n" \ "SUB %3, %3, #32\n" \ - "27:\n" \ + "30:\n" \ "MGETL D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "28:\n" \ + "31:\n" \ "MSETL [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "32:\n" \ "SUB %0, %0, #8\n" \ - "29:\n" \ + "33:\n" \ "SETL [%0++], D0.7, D1.7\n" \ "SUB %3, %3, #32\n" \ "1:" \ @@ -311,7 +315,11 @@ " .long 26b,3b\n" \ " .long 27b,3b\n" \ " .long 28b,3b\n" \ - " .long 29b,4b\n" \ + " .long 29b,3b\n" \ + " .long 30b,3b\n" \ + " .long 31b,3b\n" \ + " .long 32b,3b\n" \ + " .long 33b,4b\n" \ " .previous\n" \ : "=r" (to), "=r" (from), "=r" (ret), "=d" (n) \ : "0" (to), "1" (from), "2" (ret), "3" (n) \ @@ -402,47 +410,55 @@ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ "22:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ - "SUB %3, %3, #16\n" \ "23:\n" \ - "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "24:\n" \ - "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ "SUB %3, %3, #16\n" \ - "25:\n" \ + "24:\n" \ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "26:\n" \ + "25:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "26:\n" \ "SUB %3, %3, #16\n" \ "27:\n" \ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ "28:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "29:\n" \ + "SUB %3, %3, #16\n" \ + "30:\n" \ + "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ + "31:\n" \ + "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "32:\n" \ "SUB %3, %3, #16\n" \ "DCACHE [%1+#-64], D0Ar6\n" \ "BR $Lloop"id"\n" \ \ "MOV RAPF, %1\n" \ - "29:\n" \ + "33:\n" \ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "30:\n" \ + "34:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "35:\n" \ "SUB %3, %3, #16\n" \ - "31:\n" \ + "36:\n" \ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "32:\n" \ + "37:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "38:\n" \ "SUB %3, %3, #16\n" \ - "33:\n" \ + "39:\n" \ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "34:\n" \ + "40:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "41:\n" \ "SUB %3, %3, #16\n" \ - "35:\n" \ + "42:\n" \ "MGETD D0FrT, D0.5, D0.6, D0.7, [%1++]\n" \ - "36:\n" \ + "43:\n" \ "MSETD [%0++], D0FrT, D0.5, D0.6, D0.7\n" \ + "44:\n" \ "SUB %0, %0, #4\n" \ - "37:\n" \ + "45:\n" \ "SETD [%0++], D0.7\n" \ "SUB %3, %3, #16\n" \ "1:" \ @@ -482,7 +498,15 @@ " .long 34b,3b\n" \ " .long 35b,3b\n" \ " .long 36b,3b\n" \ - " .long 37b,4b\n" \ + " .long 37b,3b\n" \ + " .long 38b,3b\n" \ + " .long 39b,3b\n" \ + " .long 40b,3b\n" \ + " .long 41b,3b\n" \ + " .long 42b,3b\n" \ + " .long 43b,3b\n" \ + " .long 44b,3b\n" \ + " .long 45b,4b\n" \ " .previous\n" \ : "=r" (to), "=r" (from), "=r" (ret), "=d" (n) \ : "0" (to), "1" (from), "2" (ret), "3" (n) \ -- cgit v1.2.3