Re: [PATCH] x86: fix ioport unification on 32-bit [was: Re: hwclock failure in x86.git]
* Chris Wright <[EMAIL PROTECTED]> wrote: > * Ingo Molnar ([EMAIL PROTECTED]) wrote: > > thanks for tracking it down. I pulled that commit for now. But it would > > be nice to figure out what's going on there. > > Zach was right. The unification was broken for 32-bit; it was missing > the actual pushf/popf EFLAGS manipluation (set_iopl_mask()) and > would've broken task switching between processes w/ different iopl in > paravirt guests too. 64-bit sys_iopl just does pt_regs->flags > modification and lets syscall/sysret plus ptregscall sync and do > EFLAGS update. > > Also, use of volatile looks like leftover cruft. > > This patch in on top of Miguel's (can respin to standalone if that's > better). [...] thanks, applied. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] x86: fix ioport unification on 32-bit [was: Re: hwclock failure in x86.git]
* Chris Wright [EMAIL PROTECTED] wrote: * Ingo Molnar ([EMAIL PROTECTED]) wrote: thanks for tracking it down. I pulled that commit for now. But it would be nice to figure out what's going on there. Zach was right. The unification was broken for 32-bit; it was missing the actual pushf/popf EFLAGS manipluation (set_iopl_mask()) and would've broken task switching between processes w/ different iopl in paravirt guests too. 64-bit sys_iopl just does pt_regs-flags modification and lets syscall/sysret plus ptregscall sync and do EFLAGS update. Also, use of volatile looks like leftover cruft. This patch in on top of Miguel's (can respin to standalone if that's better). [...] thanks, applied. Ingo -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] x86: fix ioport unification on 32-bit [was: Re: hwclock failure in x86.git]
* Ingo Molnar ([EMAIL PROTECTED]) wrote:
> thanks for tracking it down. I pulled that commit for now. But it would
> be nice to figure out what's going on there.
Zach was right. The unification was broken for 32-bit; it was missing
the actual pushf/popf EFLAGS manipluation (set_iopl_mask()) and would've
broken task switching between processes w/ different iopl in paravirt
guests too. 64-bit sys_iopl just does pt_regs->flags modification and
lets syscall/sysret plus ptregscall sync and do EFLAGS update.
Also, use of volatile looks like leftover cruft.
This patch in on top of Miguel's (can respin to standalone if that's better).
Tested (on both 32 and 64-bit) with simple:
#include
#include
main()
{
if (iopl(3) == 0)
asm ("cli\nsti\n"::);
}
thanks,
-chris
--
From: Chris Wright <[EMAIL PROTECTED]>
Subject: [PATCH] x86: fix ioport unification on 32-bit
ioport unification was broken for 32-bit; it was missing
the acutal pushf/popf EFLAGS manipulation (set_iopl_mask()).
Also, use of volatile looks like leftover cruft.
Cc: [EMAIL PROTECTED]
Cc: Kevin Winchester <[EMAIL PROTECTED]>
Cc: Zach Brown <[EMAIL PROTECTED]>
Cc: Ingo Molnar <[EMAIL PROTECTED]>
Cc: "H. Peter Anvin" <[EMAIL PROTECTED]>
Cc: Thomas Gleixner <[EMAIL PROTECTED]>
Signed-off-by: Chris Wright <[EMAIL PROTECTED]>
---
arch/x86/kernel/ioport.c |6 --
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index e723ff3..be72d80 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -116,9 +116,10 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned
long num, int turn_on)
#ifdef CONFIG_X86_32
asmlinkage long sys_iopl(unsigned long regsp)
{
- volatile struct pt_regs *regs = (struct pt_regs *)
+ struct pt_regs *regs = (struct pt_regs *)
unsigned int level = regs->bx;
unsigned int old = (regs->flags >> 12) & 3;
+ struct thread_struct *t = >thread;
if (level > 3)
return -EINVAL;
@@ -127,8 +128,9 @@ asmlinkage long sys_iopl(unsigned long regsp)
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
}
+ t->iopl = level << 12;
regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | (level << 12);
-
+ set_iopl_mask(t->iopl);
return 0;
}
#else
--
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[PATCH] x86: fix ioport unification on 32-bit [was: Re: hwclock failure in x86.git]
* Ingo Molnar ([EMAIL PROTECTED]) wrote:
thanks for tracking it down. I pulled that commit for now. But it would
be nice to figure out what's going on there.
Zach was right. The unification was broken for 32-bit; it was missing
the actual pushf/popf EFLAGS manipluation (set_iopl_mask()) and would've
broken task switching between processes w/ different iopl in paravirt
guests too. 64-bit sys_iopl just does pt_regs-flags modification and
lets syscall/sysret plus ptregscall sync and do EFLAGS update.
Also, use of volatile looks like leftover cruft.
This patch in on top of Miguel's (can respin to standalone if that's better).
Tested (on both 32 and 64-bit) with simple:
#include stdlib.h
#include sys/io.h
main()
{
if (iopl(3) == 0)
asm (cli\nsti\n::);
}
thanks,
-chris
--
From: Chris Wright [EMAIL PROTECTED]
Subject: [PATCH] x86: fix ioport unification on 32-bit
ioport unification was broken for 32-bit; it was missing
the acutal pushf/popf EFLAGS manipulation (set_iopl_mask()).
Also, use of volatile looks like leftover cruft.
Cc: [EMAIL PROTECTED]
Cc: Kevin Winchester [EMAIL PROTECTED]
Cc: Zach Brown [EMAIL PROTECTED]
Cc: Ingo Molnar [EMAIL PROTECTED]
Cc: H. Peter Anvin [EMAIL PROTECTED]
Cc: Thomas Gleixner [EMAIL PROTECTED]
Signed-off-by: Chris Wright [EMAIL PROTECTED]
---
arch/x86/kernel/ioport.c |6 --
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index e723ff3..be72d80 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -116,9 +116,10 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned
long num, int turn_on)
#ifdef CONFIG_X86_32
asmlinkage long sys_iopl(unsigned long regsp)
{
- volatile struct pt_regs *regs = (struct pt_regs *)regsp;
+ struct pt_regs *regs = (struct pt_regs *)regsp;
unsigned int level = regs-bx;
unsigned int old = (regs-flags 12) 3;
+ struct thread_struct *t = current-thread;
if (level 3)
return -EINVAL;
@@ -127,8 +128,9 @@ asmlinkage long sys_iopl(unsigned long regsp)
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
}
+ t-iopl = level 12;
regs-flags = (regs-flags ~X86_EFLAGS_IOPL) | (level 12);
-
+ set_iopl_mask(t-iopl);
return 0;
}
#else
--
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