Commit 3dc12dfe authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/mm: Move the WARN() out of bad_kuap_fault() 



In order to prepare the removal of calls to
search_exception_tables() on the fast path, move the
WARN() out of bad_kuap_fault().

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9501311014bd6507e04b27a0c3035186ccf65cd5.1607491748.git.christophe.leroy@csgroup.eu
parent 5250d026

arch/powerpc/include/asm/book3s/32/kup.h

+1 −5
Original line number Diff line number Diff line
@@ -183,11 +183,7 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) 
	unsigned long begin = regs->kuap & 0xf0000000;

	unsigned long end = regs->kuap << 28;



	if (!is_write)

		return false;



	return WARN(address < begin || address >= end,

		    "Bug: write fault blocked by segment registers !");

	return is_write && (address < begin || address >= end);

}



#endif /* CONFIG_PPC_KUAP */

arch/powerpc/include/asm/book3s/64/kup.h

+2 −4
Original line number Diff line number Diff line
@@ -371,11 +371,9 @@ static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, 
	 * the AMR. Hence check for BLOCK_WRITE/READ against AMR.

	 */

	if (is_write) {

		return WARN(((regs->amr & AMR_KUAP_BLOCK_WRITE) == AMR_KUAP_BLOCK_WRITE),

			    "Bug: Write fault blocked by AMR!");

		return (regs->amr & AMR_KUAP_BLOCK_WRITE) == AMR_KUAP_BLOCK_WRITE;

	}

	return WARN(((regs->amr & AMR_KUAP_BLOCK_READ) == AMR_KUAP_BLOCK_READ),

		    "Bug: Read fault blocked by AMR!");

	return (regs->amr & AMR_KUAP_BLOCK_READ) == AMR_KUAP_BLOCK_READ;

}



static __always_inline void allow_user_access(void __user *to, const void __user *from,

arch/powerpc/include/asm/nohash/32/kup-8xx.h

+1 −2
Original line number Diff line number Diff line
@@ -63,8 +63,7 @@ static inline void restore_user_access(unsigned long flags) 
static inline bool

bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)

{

	return WARN(!((regs->kuap ^ MD_APG_KUAP) & 0xff000000),

		    "Bug: fault blocked by AP register !");

	return !((regs->kuap ^ MD_APG_KUAP) & 0xff000000);

}



#endif /* !__ASSEMBLY__ */

arch/powerpc/mm/fault.c

+1 −1
Original line number Diff line number Diff line
@@ -228,7 +228,7 @@ static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code, 
	// Read/write fault in a valid region (the exception table search passed

	// above), but blocked by KUAP is bad, it can never succeed.

	if (bad_kuap_fault(regs, address, is_write))

		return true;

		return WARN(true, "Bug: %s fault blocked by KUAP!", is_write ? "Write" : "Read");



	// What's left? Kernel fault on user in well defined regions (extable

	// matched), and allowed by KUAP in the faulting context.

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