On 05/26/2020 02:39 PM, Anshuman Khandual wrote:
There is no way to proceed when requested register could not be searched in
arm64_ftr_reg[]. Requesting for a non present register would be an error as
well. Hence lets just WARN_ON() when search fails in get_arm64_ftr_reg()
rather than checking for return value and doing a BUG_ON() instead in some
individual callers. But there are also caller instances that dont error out
when register search fails. Add a new helper get_arm64_ftr_reg_nowarn() for
such cases.
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
Changes in V2:
- Added get_arm64_ftr_reg_nowarn() per Will
- read_sanitised_ftr_reg() returns 0 when register search fails per Catalin
Changes in V1: (https://patchwork.kernel.org/patch/11559083/)
arch/arm64/kernel/cpufeature.c | 42 +++++++++++++++++++++++-----------
1 file changed, 29 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index bc5048f152c1..f4555b9d145c 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -548,16 +548,16 @@ static int search_cmp_ftr_reg(const void *id, const void
*regp)
}
...
static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
s64 ftr_val)
{
@@ -632,8 +654,6 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
const struct arm64_ftr_bits *ftrp;
struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
- BUG_ON(!reg);
-
for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
u64 ftr_mask = arm64_ftr_mask(ftrp);
s64 ftr_new = arm64_ftr_value(ftrp, new);
@@ -762,7 +782,6 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64
val, u64 boot)
{
struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
- BUG_ON(!regp);
update_cpu_ftr_reg(regp, val);
if ((boot & regp->strict_mask) == (val & regp->strict_mask))
return 0;
@@ -776,9 +795,6 @@ static void relax_cpu_ftr_reg(u32 sys_id, int field)
const struct arm64_ftr_bits *ftrp;
struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
- if (WARN_ON(!regp))
- return;
-
You need to return here, on !regp. Rest looks fine to me.
Suzuki
