diff options
Diffstat (limited to 'debian/patches/0002-i386-specialize-copyinmsg-and-copyoutmsg.patch')
| -rw-r--r-- | debian/patches/0002-i386-specialize-copyinmsg-and-copyoutmsg.patch | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/debian/patches/0002-i386-specialize-copyinmsg-and-copyoutmsg.patch b/debian/patches/0002-i386-specialize-copyinmsg-and-copyoutmsg.patch new file mode 100644 index 0000000..7603910 --- /dev/null +++ b/debian/patches/0002-i386-specialize-copyinmsg-and-copyoutmsg.patch @@ -0,0 +1,147 @@ +From 5e1d8cea366518faffc10bce12e073634b019469 Mon Sep 17 00:00:00 2001 +From: Justus Winter <4winter@informatik.uni-hamburg.de> +Date: Fri, 19 Dec 2014 01:51:58 +0100 +Subject: [PATCH gnumach 2/3] i386: specialize `copyinmsg' and `copyoutmsg' + +Previously, `copyinmsg' was the same function as `copyin'. The former +is for messages, and the size of messages is a multiple of four. +Likewise for `copyoutmsg'. + +Provide a specialized version of both functions. This shaves off a +couple of instructions and improves our IPC performance. + +* i386/i386/locore.S (copyinmsg): New function. +(copyout): Do not needlessly copy length to %eax first. +(copyoutmsg): New function. +--- + i386/i386/locore.S | 78 +++++++++++++++++++++++++++++++++++++++++++++++++----- + 1 file changed, 71 insertions(+), 7 deletions(-) + +diff --git a/i386/i386/locore.S b/i386/i386/locore.S +index 15715f6..ab17879 100644 +--- a/i386/i386/locore.S ++++ b/i386/i386/locore.S +@@ -1232,13 +1232,12 @@ ENTRY(discover_x86_cpu_type) + */ + + /* +- * Copy from user address space. ++ * Copy from user address space - generic version. + * arg0: user address + * arg1: kernel address + * arg2: byte count + */ + ENTRY(copyin) +-Entry(copyinmsg) + pushl %esi + pushl %edi /* save registers */ + +@@ -1275,13 +1274,43 @@ copyin_fail: + jmp copyin_ret /* pop frame and return */ + + /* +- * Copy to user address space. ++ * Copy from user address space - version for copying messages. ++ * arg0: user address ++ * arg1: kernel address ++ * arg2: byte count - must be a multiple of four ++ */ ++ENTRY(copyinmsg) ++ pushl %esi ++ pushl %edi /* save registers */ ++ ++ movl 8+S_ARG0,%esi /* get user start address */ ++ movl 8+S_ARG1,%edi /* get kernel destination address */ ++ movl 8+S_ARG2,%ecx /* get count */ ++ ++ movl $USER_DS,%eax /* use user data segment for accesses */ ++ mov %ax,%ds ++ ++ /*cld*/ /* count up: default mode in all GCC code */ ++ shrl $2,%ecx ++ RECOVER(copyin_fail) ++ rep ++ movsl /* move longwords */ ++ xorl %eax,%eax /* return 0 for success */ ++ ++ mov %ss,%di /* restore DS to kernel segment */ ++ mov %di,%ds ++ ++ popl %edi /* restore registers */ ++ popl %esi ++ ret /* and return */ ++ ++/* ++ * Copy to user address space - generic version. + * arg0: kernel address + * arg1: user address + * arg2: byte count + */ + ENTRY(copyout) +-Entry(copyoutmsg) + pushl %esi + pushl %edi /* save registers */ + +@@ -1297,14 +1326,13 @@ Entry(copyoutmsg) + jbe copyout_retry /* Use slow version on i386 */ + #endif /* !defined(MACH_HYP) && !PAE */ + +- movl %edx,%eax /* use count */ + /*cld*/ /* count up: always this way in GCC code */ +- movl %eax,%ecx /* move by longwords first */ ++ movl %edx,%ecx /* move by longwords first */ + shrl $2,%ecx + RECOVER(copyout_fail) + rep + movsl +- movl %eax,%ecx /* now move remaining bytes */ ++ movl %edx,%ecx /* now move remaining bytes */ + andl $3,%ecx + RECOVER(copyout_fail) + rep +@@ -1323,6 +1351,42 @@ copyout_fail: + movl $1,%eax /* return 1 for failure */ + jmp copyout_ret /* pop frame and return */ + ++/* ++ * Copy to user address space - version for copying messages. ++ * arg0: kernel address ++ * arg1: user address ++ * arg2: byte count - must be a multiple of four ++ */ ++ENTRY(copyoutmsg) ++ pushl %esi ++ pushl %edi /* save registers */ ++ ++ movl 8+S_ARG0,%esi /* get kernel start address */ ++ movl 8+S_ARG1,%edi /* get user start address */ ++ movl 8+S_ARG2,%ecx /* get count */ ++ ++ movl $USER_DS,%eax /* use user data segment for accesses */ ++ mov %ax,%es ++ ++#if !defined(MACH_HYP) && !PAE ++ movl 8+S_ARG2,%edx /* copyout_retry expects count here */ ++ cmpl $3,machine_slot+SUB_TYPE_CPU_TYPE ++ jbe copyout_retry /* Use slow version on i386 */ ++#endif /* !defined(MACH_HYP) && !PAE */ ++ ++ shrl $2,%ecx /* move by longwords */ ++ RECOVER(copyout_fail) ++ rep ++ movsl ++ xorl %eax,%eax /* return 0 for success */ ++ ++ mov %ss,%di /* restore ES to kernel segment */ ++ mov %di,%es ++ ++ popl %edi /* restore registers */ ++ popl %esi ++ ret /* and return */ ++ + #if !defined(MACH_HYP) && !PAE + /* + * Check whether user address space is writable +-- +2.1.3 + |