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x86/entry/32: Enable pt_regs based syscalls

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Enable pt_regs based syscalls for 32-bit.  This makes the 32-bit native
kernel consistent with the 64-bit kernel, and improves the syscall
interface by not needing to push all 6 potential arguments onto the stack.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://lkml.kernel.org/r/20200313195144.164260-17-brgerst@gmail.com
This commit is contained in:
Brian Gerst
2020-03-13 15:51:42 -04:00
committed by Thomas Gleixner
parent 121b32a58a
commit 25c619e59b
6 changed files with 64 additions and 114 deletions
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15
arch/x86/entry/common.c
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@@ -333,20 +333,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
if (likely(nr < IA32_NR_syscalls)) {
nr = array_index_nospec(nr, IA32_NR_syscalls);
#ifdef CONFIG_IA32_EMULATION
regs->ax = ia32_sys_call_table[nr](regs);
#else
/*
* It's possible that a 32-bit syscall implementation
* takes a 64-bit parameter but nonetheless assumes that
* the high bits are zero. Make sure we zero-extend all
* of the args.
*/
regs->ax = ia32_sys_call_table[nr](
(unsigned int)regs->bx, (unsigned int)regs->cx,
(unsigned int)regs->dx, (unsigned int)regs->si,
(unsigned int)regs->di, (unsigned int)regs->bp);
#endif /* CONFIG_IA32_EMULATION */
}
syscall_return_slowpath(regs);
@@ -439,9 +426,7 @@ __visible long do_fast_syscall_32(struct pt_regs *regs)
}
#endif
#ifdef CONFIG_X86_64
SYSCALL_DEFINE0(ni_syscall)
{
return -ENOSYS;
}
#endif