Commit cdb1ea02 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/pseries: add new branch prediction security bits for link stack 



The hypervisor interface has defined branch prediction security bits for
handling the link stack. Wire them up.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200825075612.224656-1-npiggin@gmail.com
parent 05504b42

arch/powerpc/include/asm/hvcall.h

+2 −0
Original line number Diff line number Diff line
@@ -375,11 +375,13 @@ 
#define H_CPU_CHAR_THREAD_RECONFIG_CTRL	(1ull << 57) // IBM bit 6

#define H_CPU_CHAR_COUNT_CACHE_DISABLED	(1ull << 56) // IBM bit 7

#define H_CPU_CHAR_BCCTR_FLUSH_ASSIST	(1ull << 54) // IBM bit 9

#define H_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST (1ull << 52) // IBM bit 11



#define H_CPU_BEHAV_FAVOUR_SECURITY	(1ull << 63) // IBM bit 0

#define H_CPU_BEHAV_L1D_FLUSH_PR	(1ull << 62) // IBM bit 1

#define H_CPU_BEHAV_BNDS_CHK_SPEC_BAR	(1ull << 61) // IBM bit 2

#define H_CPU_BEHAV_FLUSH_COUNT_CACHE	(1ull << 58) // IBM bit 5

#define H_CPU_BEHAV_FLUSH_LINK_STACK	(1ull << 57) // IBM bit 6



/* Flag values used in H_REGISTER_PROC_TBL hcall */

#define PROC_TABLE_OP_MASK	0x18

arch/powerpc/platforms/pseries/setup.c

+6 −0
Original line number Diff line number Diff line
@@ -519,9 +519,15 @@ static void init_cpu_char_feature_flags(struct h_cpu_char_result *result) 
	if (result->character & H_CPU_CHAR_BCCTR_FLUSH_ASSIST)

		security_ftr_set(SEC_FTR_BCCTR_FLUSH_ASSIST);



	if (result->character & H_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST)

		security_ftr_set(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST);



	if (result->behaviour & H_CPU_BEHAV_FLUSH_COUNT_CACHE)

		security_ftr_set(SEC_FTR_FLUSH_COUNT_CACHE);



	if (result->behaviour & H_CPU_BEHAV_FLUSH_LINK_STACK)

		security_ftr_set(SEC_FTR_FLUSH_LINK_STACK);



	/*

	 * The features below are enabled by default, so we instead look to see

	 * if firmware has *disabled* them, and clear them if so.

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