Messages in this thread | | | Date | Tue, 8 Feb 2022 14:16:46 +0100 | Subject | Re: [PATCH v2 01/11] s390/uaccess: Add copy_from/to_user_key functions | From | Christian Borntraeger <> |
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Am 08.02.22 um 13:31 schrieb Christian Borntraeger: > Am 07.02.22 um 17:59 schrieb Janis Schoetterl-Glausch: >> Add copy_from/to_user_key functions, which perform storage key checking. >> These functions can be used by KVM for emulating instructions that need >> to be key checked. >> These functions differ from their non _key counterparts in >> include/linux/uaccess.h only in the additional key argument and must be >> kept in sync with those. >> >> Since the existing uaccess implementation on s390 makes use of move >> instructions that support having an additional access key supplied, >> we can implement raw_copy_from/to_user_key by enhancing the >> existing implementation. >> >> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> > > Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> please use Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com> instead... > >> --- >> arch/s390/include/asm/uaccess.h | 22 +++++++++ >> arch/s390/lib/uaccess.c | 81 +++++++++++++++++++++++++-------- >> 2 files changed, 85 insertions(+), 18 deletions(-) >> >> diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h >> index d74e26b48604..ba1bcb91af95 100644 >> --- a/arch/s390/include/asm/uaccess.h >> +++ b/arch/s390/include/asm/uaccess.h >> @@ -44,6 +44,28 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n); >> #define INLINE_COPY_TO_USER >> #endif >> +unsigned long __must_check >> +_copy_from_user_key(void *to, const void __user *from, unsigned long n, unsigned long key); >> + >> +static __always_inline unsigned long __must_check >> +copy_from_user_key(void *to, const void __user *from, unsigned long n, unsigned long key) >> +{ >> + if (likely(check_copy_size(to, n, false))) >> + n = _copy_from_user_key(to, from, n, key); >> + return n; >> +} >> + >> +unsigned long __must_check >> +_copy_to_user_key(void __user *to, const void *from, unsigned long n, unsigned long key); >> + >> +static __always_inline unsigned long __must_check >> +copy_to_user_key(void __user *to, const void *from, unsigned long n, unsigned long key) >> +{ >> + if (likely(check_copy_size(from, n, true))) >> + n = _copy_to_user_key(to, from, n, key); >> + return n; >> +} >> + >> int __put_user_bad(void) __attribute__((noreturn)); >> int __get_user_bad(void) __attribute__((noreturn)); >> diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c >> index 8a5d21461889..b709239feb5d 100644 >> --- a/arch/s390/lib/uaccess.c >> +++ b/arch/s390/lib/uaccess.c >> @@ -59,11 +59,13 @@ static inline int copy_with_mvcos(void) >> #endif >> static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr, >> - unsigned long size) >> + unsigned long size, unsigned long key) >> { >> unsigned long tmp1, tmp2; >> union oac spec = { >> + .oac2.key = key, >> .oac2.as = PSW_BITS_AS_SECONDARY, >> + .oac2.k = 1, >> .oac2.a = 1, >> }; >> @@ -94,19 +96,19 @@ static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr >> } >> static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, >> - unsigned long size) >> + unsigned long size, unsigned long key) >> { >> unsigned long tmp1, tmp2; >> tmp1 = -256UL; >> asm volatile( >> " sacf 0\n" >> - "0: mvcp 0(%0,%2),0(%1),%3\n" >> + "0: mvcp 0(%0,%2),0(%1),%[key]\n" >> "7: jz 5f\n" >> "1: algr %0,%3\n" >> " la %1,256(%1)\n" >> " la %2,256(%2)\n" >> - "2: mvcp 0(%0,%2),0(%1),%3\n" >> + "2: mvcp 0(%0,%2),0(%1),%[key]\n" >> "8: jnz 1b\n" >> " j 5f\n" >> "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ >> @@ -115,7 +117,7 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, >> " slgr %4,%1\n" >> " clgr %0,%4\n" /* copy crosses next page boundary? */ >> " jnh 6f\n" >> - "4: mvcp 0(%4,%2),0(%1),%3\n" >> + "4: mvcp 0(%4,%2),0(%1),%[key]\n" >> "9: slgr %0,%4\n" >> " j 6f\n" >> "5: slgr %0,%0\n" >> @@ -123,24 +125,49 @@ static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr, >> EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) >> EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) >> : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) >> - : : "cc", "memory"); >> + : [key] "d" (key << 4) >> + : "cc", "memory"); >> return size; >> } >> -unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) >> +static unsigned long raw_copy_from_user_key(void *to, const void __user *from, >> + unsigned long n, unsigned long key) >> { >> if (copy_with_mvcos()) >> - return copy_from_user_mvcos(to, from, n); >> - return copy_from_user_mvcp(to, from, n); >> + return copy_from_user_mvcos(to, from, n, key); >> + return copy_from_user_mvcp(to, from, n, key); >> +} >> + >> +unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) >> +{ >> + return raw_copy_from_user_key(to, from, n, 0); >> } >> EXPORT_SYMBOL(raw_copy_from_user); >> +unsigned long _copy_from_user_key(void *to, const void __user *from, >> + unsigned long n, unsigned long key) >> +{ >> + unsigned long res = n; >> + >> + might_fault(); >> + if (!should_fail_usercopy()) { >> + instrument_copy_from_user(to, from, n); >> + res = raw_copy_from_user_key(to, from, n, key); >> + } >> + if (unlikely(res)) >> + memset(to + (n - res), 0, res); >> + return res; >> +} >> +EXPORT_SYMBOL(_copy_from_user_key); >> + >> static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, >> - unsigned long size) >> + unsigned long size, unsigned long key) >> { >> unsigned long tmp1, tmp2; >> union oac spec = { >> + .oac1.key = key, >> .oac1.as = PSW_BITS_AS_SECONDARY, >> + .oac1.k = 1, >> .oac1.a = 1, >> }; >> @@ -171,19 +198,19 @@ static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x, >> } >> static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, >> - unsigned long size) >> + unsigned long size, unsigned long key) >> { >> unsigned long tmp1, tmp2; >> tmp1 = -256UL; >> asm volatile( >> " sacf 0\n" >> - "0: mvcs 0(%0,%1),0(%2),%3\n" >> + "0: mvcs 0(%0,%1),0(%2),%[key]\n" >> "7: jz 5f\n" >> "1: algr %0,%3\n" >> " la %1,256(%1)\n" >> " la %2,256(%2)\n" >> - "2: mvcs 0(%0,%1),0(%2),%3\n" >> + "2: mvcs 0(%0,%1),0(%2),%[key]\n" >> "8: jnz 1b\n" >> " j 5f\n" >> "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ >> @@ -192,7 +219,7 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, >> " slgr %4,%1\n" >> " clgr %0,%4\n" /* copy crosses next page boundary? */ >> " jnh 6f\n" >> - "4: mvcs 0(%4,%1),0(%2),%3\n" >> + "4: mvcs 0(%4,%1),0(%2),%[key]\n" >> "9: slgr %0,%4\n" >> " j 6f\n" >> "5: slgr %0,%0\n" >> @@ -200,18 +227,36 @@ static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x, >> EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) >> EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) >> : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) >> - : : "cc", "memory"); >> + : [key] "d" (key << 4) >> + : "cc", "memory"); >> return size; >> } >> -unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) >> +static unsigned long raw_copy_to_user_key(void __user *to, const void *from, >> + unsigned long n, unsigned long key) >> { >> if (copy_with_mvcos()) >> - return copy_to_user_mvcos(to, from, n); >> - return copy_to_user_mvcs(to, from, n); >> + return copy_to_user_mvcos(to, from, n, key); >> + return copy_to_user_mvcs(to, from, n, key); >> +} >> + >> +unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) >> +{ >> + return raw_copy_to_user_key(to, from, n, 0); >> } >> EXPORT_SYMBOL(raw_copy_to_user); >> +unsigned long _copy_to_user_key(void __user *to, const void *from, >> + unsigned long n, unsigned long key) >> +{ >> + might_fault(); >> + if (should_fail_usercopy()) >> + return n; >> + instrument_copy_to_user(to, from, n); >> + return raw_copy_to_user_key(to, from, n, key); >> +} >> +EXPORT_SYMBOL(_copy_to_user_key); >> + >> static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size) >> { >> unsigned long tmp1, tmp2;
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