diff mbox series

[v2,2/2] s390x: Add 3f program exception handler

Message ID 20200907124700.10374-3-frankja@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series s390x: pv: Fixes and improvements | expand

Commit Message

Janosch Frank Sept. 7, 2020, 12:47 p.m. UTC 
Program exception 3f (secure storage violation) can only be detected
when the CPU is running in SIE with a format 4 state description,
e.g. running a protected guest. Because of this and because user
space partly controls the guest memory mapping and can trigger this
exception, we want to send a SIGSEGV to the process running the guest
and not panic the kernel.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
CC: <stable@vger.kernel.org> # 5.7+
Fixes: 084ea4d611a3 ("s390/mm: add (non)secure page access exceptions handlers")
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/kernel/pgm_check.S |  2 +-
 arch/s390/mm/fault.c         | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

Comments

Cornelia Huck Sept. 8, 2020, 6:39 a.m. UTC | #1 
On Mon,  7 Sep 2020 08:47:00 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> Program exception 3f (secure storage violation) can only be detected
> when the CPU is running in SIE with a format 4 state description,
> e.g. running a protected guest. Because of this and because user
> space partly controls the guest memory mapping and can trigger this
> exception, we want to send a SIGSEGV to the process running the guest
> and not panic the kernel.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> CC: <stable@vger.kernel.org> # 5.7+
> Fixes: 084ea4d611a3 ("s390/mm: add (non)secure page access exceptions handlers")
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/kernel/pgm_check.S |  2 +-
>  arch/s390/mm/fault.c         | 20 ++++++++++++++++++++
>  2 files changed, 21 insertions(+), 1 deletion(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Heiko Carstens Sept. 8, 2020, 7:53 a.m. UTC | #2 
Hi Janosch,

On Tue, Sep 08, 2020 at 05:56:19AM +0800, kernel test robot wrote:
> All warnings (new ones prefixed by >>):
> 
> >> arch/s390/mm/fault.c:862:6: warning: no previous prototype for 'do_secure_storage_violation' [-Wmissing-prototypes]
>      862 | void do_secure_storage_violation(struct pt_regs *regs)
>          |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> # https://github.com/0day-ci/linux/commit/4aee662164217d48d050e0d9cf57a2cb2cdeaa8a
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Janosch-Frank/s390x-pv-Fixes-and-improvements/20200908-021233
> git checkout 4aee662164217d48d050e0d9cf57a2cb2cdeaa8a
> vim +/do_secure_storage_violation +862 arch/s390/mm/fault.c
> 
>    861	
>  > 862	void do_secure_storage_violation(struct pt_regs *regs)

To get rid of this warning, please add the function prototype to
arch/s390/kernel/entry.h. Like we have them for all other program
check handlers for this reason as well.
kernel test robot Sept. 8, 2020, 7:58 a.m. UTC | #3 
Hi Janosch,

I love your patch! Perhaps something to improve:

[auto build test WARNING on s390/features]
[also build test WARNING on v5.9-rc4 next-20200903]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Janosch-Frank/s390x-pv-Fixes-and-improvements/20200908-021233
base:   https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features
config: s390-randconfig-r032-20200908 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 5f5a0bb0872a9673bad08b38bc0b14c42263902a)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:20:12: note: expanded from macro '___constant_swab32'
           (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) |            \
                     ^
   In file included from arch/s390/mm/fault.c:35:
   In file included from arch/s390/include/asm/diag.h:12:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:31:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32'
           (((__u32)(x) & (__u32)0x00ff0000UL) >>  8) |            \
                     ^
   In file included from arch/s390/mm/fault.c:35:
   In file included from arch/s390/include/asm/diag.h:12:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:31:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32'
           (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
                     ^
   In file included from arch/s390/mm/fault.c:35:
   In file included from arch/s390/include/asm/diag.h:12:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:31:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:120:12: note: expanded from macro '__swab32'
           __fswab32(x))
                     ^
   In file included from arch/s390/mm/fault.c:35:
   In file included from arch/s390/include/asm/diag.h:12:
   In file included from include/linux/if_ether.h:19:
   In file included from include/linux/skbuff.h:31:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> arch/s390/mm/fault.c:862:6: warning: no previous prototype for function 'do_secure_storage_violation' [-Wmissing-prototypes]
   void do_secure_storage_violation(struct pt_regs *regs)
        ^
   arch/s390/mm/fault.c:862:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void do_secure_storage_violation(struct pt_regs *regs)
   ^
   static 
   21 warnings generated.

# https://github.com/0day-ci/linux/commit/4aee662164217d48d050e0d9cf57a2cb2cdeaa8a
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Janosch-Frank/s390x-pv-Fixes-and-improvements/20200908-021233
git checkout 4aee662164217d48d050e0d9cf57a2cb2cdeaa8a
vim +/do_secure_storage_violation +862 arch/s390/mm/fault.c

   861	
 > 862	void do_secure_storage_violation(struct pt_regs *regs)
   863	{
   864		/*
   865		 * Either KVM messed up the secure guest mapping or the same
   866		 * page is mapped into multiple secure guests.
   867		 *
   868		 * This exception is only triggered when a guest 2 is running
   869		 * and can therefore never occur in kernel context.
   870		 */
   871		printk_ratelimited(KERN_WARNING
   872				   "Secure storage violation in task: %s, pid %d\n",
   873				   current->comm, current->pid);
   874		send_sig(SIGSEGV, current, 0);
   875	}
   876	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/arch/s390/kernel/pgm_check.S b/arch/s390/kernel/pgm_check.S
index 2c27907a5ffc..9a92638360ee 100644
--- a/arch/s390/kernel/pgm_check.S
+++ b/arch/s390/kernel/pgm_check.S
@@ -80,7 +80,7 @@  PGM_CHECK(do_dat_exception)		/* 3b */
 PGM_CHECK_DEFAULT			/* 3c */
 PGM_CHECK(do_secure_storage_access)	/* 3d */
 PGM_CHECK(do_non_secure_storage_access)	/* 3e */
-PGM_CHECK_DEFAULT			/* 3f */
+PGM_CHECK(do_secure_storage_violation)	/* 3f */
 PGM_CHECK(monitor_event_exception)	/* 40 */
 PGM_CHECK_DEFAULT			/* 41 */
 PGM_CHECK_DEFAULT			/* 42 */
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 4c8c063bce5b..996884dcc9fd 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -859,6 +859,21 @@  void do_non_secure_storage_access(struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(do_non_secure_storage_access);
 
+void do_secure_storage_violation(struct pt_regs *regs)
+{
+	/*
+	 * Either KVM messed up the secure guest mapping or the same
+	 * page is mapped into multiple secure guests.
+	 *
+	 * This exception is only triggered when a guest 2 is running
+	 * and can therefore never occur in kernel context.
+	 */
+	printk_ratelimited(KERN_WARNING
+			   "Secure storage violation in task: %s, pid %d\n",
+			   current->comm, current->pid);
+	send_sig(SIGSEGV, current, 0);
+}
+
 #else
 void do_secure_storage_access(struct pt_regs *regs)
 {
@@ -869,4 +884,9 @@  void do_non_secure_storage_access(struct pt_regs *regs)
 {
 	default_trap_handler(regs);
 }
+
+void do_secure_storage_violation(struct pt_regs *regs)
+{
+	default_trap_handler(regs);
+}
 #endif