Commit 7ba68b21 authored by Jordan Niethe's avatar Jordan Niethe Committed by Michael Ellerman
Browse files

powerpc: Add a probe_user_read_inst() function 



Introduce a probe_user_read_inst() function to use in cases where
probe_user_read() is used for getting an instruction. This will be
more useful for prefixed instructions.

Signed-off-by: default avatarJordan Niethe <jniethe5@gmail.com>
Reviewed-by: default avatarAlistair Popple <alistair@popple.id.au>
[mpe: Don't write to *inst on error, fold in __user annotations]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-14-jniethe5@gmail.com
parent f8faaffa

arch/powerpc/include/asm/inst.h

+3 −0
Original line number Diff line number Diff line
@@ -37,4 +37,7 @@ static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y) 
	return ppc_inst_val(x) == ppc_inst_val(y);

}



int probe_user_read_inst(struct ppc_inst *inst,

			 struct ppc_inst __user *nip);



#endif /* _ASM_POWERPC_INST_H */

arch/powerpc/lib/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ CFLAGS_code-patching.o += -DDISABLE_BRANCH_PROFILING 
CFLAGS_feature-fixups.o += -DDISABLE_BRANCH_PROFILING

endif



obj-y += alloc.o code-patching.o feature-fixups.o pmem.o

obj-y += alloc.o code-patching.o feature-fixups.o pmem.o inst.o



ifndef CONFIG_KASAN

obj-y	+=	string.o memcmp_$(BITS).o

arch/powerpc/lib/inst.c

0 → 100644
+20 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 *  Copyright 2020, IBM Corporation.

 */



#include <linux/uaccess.h>

#include <asm/inst.h>



int probe_user_read_inst(struct ppc_inst *inst,

			 struct ppc_inst __user *nip)

{

	unsigned int val;

	int err;



	err = probe_user_read(&val, nip, sizeof(val));

	if (!err)

		*inst = ppc_inst(val);



	return err;

}

arch/powerpc/mm/fault.c

+2 −2
Original line number Diff line number Diff line
@@ -282,7 +282,7 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address, 
	 * expand to 1MB without further checks.

	 */

	if (address + 0x100000 < vma->vm_end) {

		unsigned int __user *nip = (unsigned int __user *)regs->nip;

		struct ppc_inst __user *nip = (struct ppc_inst __user *)regs->nip;

		/* get user regs even if this fault is in kernel mode */

		struct pt_regs *uregs = current->thread.regs;

		if (uregs == NULL)
@@ -307,7 +307,7 @@ static bool bad_stack_expansion(struct pt_regs *regs, unsigned long address, 
		    access_ok(nip, sizeof(*nip))) {

			struct ppc_inst inst;



			if (!probe_user_read(&inst, nip, sizeof(inst)))

			if (!probe_user_read_inst(&inst, nip))

				return !store_updates_sp(inst);

			*must_retry = true;

		}