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powerpc/security: change link stack flush state to the flush type enum

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Prepare to allow for hardware link stack flushing by using the
none/sw/hw type, same as the count cache state.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200609070610.846703-3-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2020-06-09 17:06:05 +10:00 committed by Michael Ellerman
parent 1026798c64
commit c06ac27710
1 changed files with 5 additions and 5 deletions
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10
arch/powerpc/kernel/security.c
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@ -27,7 +27,7 @@ enum branch_cache_flush_type {
BRANCH_CACHE_FLUSH_HW = 0x4,
};
static enum branch_cache_flush_type count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;
static bool link_stack_flush_enabled;
static enum branch_cache_flush_type link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;
bool barrier_nospec_enabled;
static bool no_nospec;
@ -219,7 +219,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
if (ccd)
seq_buf_printf(&s, "Indirect branch cache disabled");
if (link_stack_flush_enabled)
if (link_stack_flush_type == BRANCH_CACHE_FLUSH_SW)
seq_buf_printf(&s, ", Software link stack flush");
} else if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
@ -228,7 +228,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW)
seq_buf_printf(&s, " (hardware accelerated)");
if (link_stack_flush_enabled)
if (link_stack_flush_type == BRANCH_CACHE_FLUSH_SW)
seq_buf_printf(&s, ", Software link stack flush");
} else if (btb_flush_enabled) {
@ -447,7 +447,7 @@ static void toggle_branch_cache_flush(bool enable)
ppc_inst(PPC_INST_NOP));
#endif
pr_info("link-stack-flush: software flush disabled.\n");
link_stack_flush_enabled = false;
link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;
no_count_cache_flush();
return;
}
@ -463,7 +463,7 @@ static void toggle_branch_cache_flush(bool enable)
#endif
pr_info("link-stack-flush: software flush enabled.\n");
link_stack_flush_enabled = true;
link_stack_flush_type = BRANCH_CACHE_FLUSH_SW;
// If we just need to flush the link stack, patch an early return
if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {