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x86/ptrace: Cleanup the definition of the pt_regs structure

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struct pt_regs is hard to read because the member or section related
comments are not aligned with the members.

The 'cs' and 'ss' members of pt_regs are type of 'unsigned long' while
in reality they are only 16-bit wide. This works so far as the
remaining space is unused, but FRED will use the remaining bits for
other purposes.

To prepare for FRED:

  - Cleanup the formatting
  - Convert 'cs' and 'ss' to u16 and embed them into an union
    with a u64
  - Fixup the related printk() format strings

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Originally-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Shan Kang <shan.kang@intel.com>
Link: https://lore.kernel.org/r/20231205105030.8698-14-xin3.li@intel.com
This commit is contained in:
Xin Li 2023-12-05 02:50:02 -08:00 committed by Borislav Petkov (AMD)
parent cd6df3f378
commit ee63291aa8
3 changed files with 37 additions and 15 deletions
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2
arch/x86/entry/vsyscall/vsyscall_64.c
View File

@ -76,7 +76,7 @@ static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
if (!show_unhandled_signals)
return;
printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
printk_ratelimited("%s%s[%d] %s ip:%lx cs:%x sp:%lx ax:%lx si:%lx di:%lx\n",
level, current->comm, task_pid_nr(current),
message, regs->ip, regs->cs,
regs->sp, regs->ax, regs->si, regs->di);

48
arch/x86/include/asm/ptrace.h
View File

@ -57,17 +57,19 @@ struct pt_regs {
#else /* __i386__ */
struct pt_regs {
/*
* C ABI says these regs are callee-preserved. They aren't saved on kernel entry
* unless syscall needs a complete, fully filled "struct pt_regs".
*/
/*
* C ABI says these regs are callee-preserved. They aren't saved on
* kernel entry unless syscall needs a complete, fully filled
* "struct pt_regs".
*/
unsigned long r15;
unsigned long r14;
unsigned long r13;
unsigned long r12;
unsigned long bp;
unsigned long bx;
/* These regs are callee-clobbered. Always saved on kernel entry. */
/* These regs are callee-clobbered. Always saved on kernel entry. */
unsigned long r11;
unsigned long r10;
unsigned long r9;
@ -77,18 +79,38 @@ struct pt_regs {
unsigned long dx;
unsigned long si;
unsigned long di;
/*
* On syscall entry, this is syscall#. On CPU exception, this is error code.
* On hw interrupt, it's IRQ number:
*/
/*
* orig_ax is used on entry for:
* - the syscall number (syscall, sysenter, int80)
* - error_code stored by the CPU on traps and exceptions
* - the interrupt number for device interrupts
*/
unsigned long orig_ax;
/* Return frame for iretq */
/* The IRETQ return frame starts here */
unsigned long ip;
unsigned long cs;
union {
/* The full 64-bit data slot containing CS */
u64 csx;
/* CS selector */
u16 cs;
};
unsigned long flags;
unsigned long sp;
unsigned long ss;
/* top of stack page */
union {
/* The full 64-bit data slot containing SS */
u64 ssx;
/* SS selector */
u16 ss;
};
/*
* Top of stack on IDT systems.
*/
};
#endif /* !__i386__ */

2
arch/x86/kernel/process_64.c
View File

@ -117,7 +117,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
printk("%sFS: %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
log_lvl, fs, fsindex, gs, gsindex, shadowgs);
printk("%sCS: %04lx DS: %04x ES: %04x CR0: %016lx\n",
printk("%sCS: %04x DS: %04x ES: %04x CR0: %016lx\n",
log_lvl, regs->cs, ds, es, cr0);
printk("%sCR2: %016lx CR3: %016lx CR4: %016lx\n",
log_lvl, cr2, cr3, cr4);