From: Andrea Arcangeli <andrea@suse.de>
To: Marcelo Tosatti <marcelo@conectiva.com.br>
Cc: Linus Torvalds <torvalds@transmeta.com>, linux-kernel@vger.kernel.org
Subject: x86 FPU fixes for 2.4.19pre7
Date: Fri, 26 Apr 2002 12:58:27 +0200 [thread overview]
Message-ID: <20020426125827.M1337@dualathlon.random> (raw)
Marcelo, please review and merge these below fixes in next mainline.
this one is from pre7aa1:
--- 2.4.19pre6aa2/arch/i386/kernel/i387.c.~1~ Sun Apr 1 01:17:07 2001
+++ 2.4.19pre6aa2/arch/i386/kernel/i387.c Mon Apr 15 01:21:58 2002
@@ -349,13 +349,15 @@
static inline int restore_i387_fxsave( struct _fpstate *buf )
{
+ int err;
struct task_struct *tsk = current;
clear_fpu( tsk );
- if ( __copy_from_user( &tsk->thread.i387.fxsave, &buf->_fxsr_env[0],
- sizeof(struct i387_fxsave_struct) ) )
- return 1;
+ err = __copy_from_user(&tsk->thread.i387.fxsave, &buf->_fxsr_env[0],
+ sizeof(struct i387_fxsave_struct));
/* mxcsr bit 6 and 31-16 must be zero for security reasons */
tsk->thread.i387.fxsave.mxcsr &= 0xffbf;
+ if (err)
+ return 1;
return convert_fxsr_from_user( &tsk->thread.i387.fxsave, buf );
}
this one from pre7aa2:
diff -urN 2.4.19pre7/arch/i386/kernel/i387.c mmx/arch/i386/kernel/i387.c
--- 2.4.19pre7/arch/i386/kernel/i387.c Sun Apr 1 01:17:07 2001
+++ mmx/arch/i386/kernel/i387.c Fri Apr 26 10:56:02 2002
@@ -10,6 +10,7 @@
#include <linux/config.h>
#include <linux/sched.h>
+#include <linux/init.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/math_emu.h>
@@ -24,6 +25,29 @@
#define HAVE_HWFP 1
#endif
+static union i387_union empty_fpu_state;
+
+void __init boot_init_fpu(void)
+{
+ memset(&empty_fpu_state, 0, sizeof(union i387_union));
+
+ if (!cpu_has_fxsr) {
+ empty_fpu_state.fsave.cwd = 0xffff037f;
+ empty_fpu_state.fsave.swd = 0xffff0000;
+ empty_fpu_state.fsave.twd = 0xffffffff;
+ empty_fpu_state.fsave.fos = 0xffff0000;
+ } else {
+ empty_fpu_state.fxsave.cwd = 0x37f;
+ if (cpu_has_xmm)
+ empty_fpu_state.fxsave.mxcsr = 0x1f80;
+ }
+}
+
+void load_empty_fpu(struct task_struct * tsk)
+{
+ memcpy(&tsk->thread.i387, &empty_fpu_state, sizeof(union i387_union));
+}
+
/*
* The _current_ task is using the FPU for the first time
* so initialize it and set the mxcsr to its default
@@ -32,10 +56,10 @@
*/
void init_fpu(void)
{
- __asm__("fninit");
- if ( cpu_has_xmm )
- load_mxcsr(0x1f80);
-
+ if (cpu_has_fxsr)
+ asm volatile("fxrstor %0" : : "m" (empty_fpu_state.fxsave));
+ else
+ __asm__("fninit");
current->used_math = 1;
}
diff -urN 2.4.19pre7/arch/i386/kernel/ptrace.c mmx/arch/i386/kernel/ptrace.c
--- 2.4.19pre7/arch/i386/kernel/ptrace.c Tue Jan 22 18:55:43 2002
+++ mmx/arch/i386/kernel/ptrace.c Fri Apr 26 10:56:02 2002
@@ -369,12 +369,8 @@
break;
}
ret = 0;
- if ( !child->used_math ) {
- /* Simulate an empty FPU. */
- set_fpu_cwd(child, 0x037f);
- set_fpu_swd(child, 0x0000);
- set_fpu_twd(child, 0xffff);
- }
+ if ( !child->used_math )
+ load_empty_fpu(child);
get_fpregs((struct user_i387_struct *)data, child);
break;
}
@@ -397,13 +393,8 @@
ret = -EIO;
break;
}
- if ( !child->used_math ) {
- /* Simulate an empty FPU. */
- set_fpu_cwd(child, 0x037f);
- set_fpu_swd(child, 0x0000);
- set_fpu_twd(child, 0xffff);
- set_fpu_mxcsr(child, 0x1f80);
- }
+ if ( !child->used_math )
+ load_empty_fpu(child);
ret = get_fpxregs((struct user_fxsr_struct *)data, child);
break;
}
diff -urN 2.4.19pre7/include/asm-i386/bugs.h mmx/include/asm-i386/bugs.h
--- 2.4.19pre7/include/asm-i386/bugs.h Fri Apr 26 10:36:12 2002
+++ mmx/include/asm-i386/bugs.h Fri Apr 26 10:56:52 2002
@@ -204,7 +204,10 @@
static void __init check_bugs(void)
{
+ extern void __init boot_init_fpu(void);
+
identify_cpu(&boot_cpu_data);
+ boot_init_fpu();
#ifndef CONFIG_SMP
printk("CPU: ");
print_cpu_info(&boot_cpu_data);
diff -urN 2.4.19pre7/include/asm-i386/i387.h mmx/include/asm-i386/i387.h
--- 2.4.19pre7/include/asm-i386/i387.h Sat Apr 20 09:43:17 2002
+++ mmx/include/asm-i386/i387.h Fri Apr 26 10:56:02 2002
@@ -76,6 +76,7 @@
struct task_struct *tsk );
extern int set_fpxregs( struct task_struct *tsk,
struct user_fxsr_struct *buf );
+extern void load_empty_fpu(struct task_struct *);
/*
* FPU state for core dumps...
Thanks,
Andrea
reply other threads:[~2002-04-26 10:58 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20020426125827.M1337@dualathlon.random \
--to=andrea@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=marcelo@conectiva.com.br \
--cc=torvalds@transmeta.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®