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arm64: Support more ID register field types

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Add MRS_EXACT_IF_DIFFERENT, MRS_HIGHER_OR_ZERO, and MRS_HIGHER.

These will be used to handle the cache CTR_EL0 register, and make some
ID register values safer.

They are:
 - MRS_EXACT_IF_DIFFERENT: If the field is the same on all CPUs then
                           use this value, otherwise use the safe value.
 - MRS_HIGHER_OR_ZERO: Use the highest value, or zero if seen,
 - MRS_HIGHER: Use the highest value.

Reviewed by:	imp
Sponsored by:	Arm Ltd
Differential Revision:	https://reviews.freebsd.org/D47122
This commit is contained in:
Andrew Turner 2024-10-18 10:16:41 +01:00
parent f031499405
commit f1fb1d5c90
1 changed files with 30 additions and 5 deletions
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35
sys/arm64/arm64/identcpu.c
View File

@ -292,7 +292,10 @@ const struct cpu_implementers cpu_implementers[] = {
#define MRS_TYPE_MASK 0xf
#define MRS_INVALID 0
#define MRS_EXACT 1
#define MRS_LOWER 2
#define MRS_EXACT_IF_DIFFERENT 2
#define MRS_LOWER 3
#define MRS_HIGHER_OR_ZERO 4
#define MRS_HIGHER 5
#define MRS_SAFE_SHIFT 4
#define MRS_SAFE_MASK (0xfu << MRS_SAFE_SHIFT)
#define MRS_SAFE(x) (((x) << MRS_SAFE_SHIFT) & MRS_SAFE_MASK)
@ -2175,19 +2178,41 @@ static uint64_t
update_special_reg_field(uint64_t user_reg, u_int type, uint64_t value,
u_int width, u_int shift, bool sign)
{
uint64_t cur, mask, new_val;
mask = ((1ul << width) - 1) << shift;
cur = user_reg & mask;
new_val = value & mask;
switch (type & MRS_TYPE_MASK) {
case MRS_EXACT_IF_DIFFERENT:
if (mrs_field_cmp(cur, new_val, shift, width, sign) != 0)
break;
/* FALLTHROUGH */
case MRS_EXACT:
user_reg &= ~(0xful << shift);
user_reg |= (uint64_t)MRS_SAFE(type) << shift;
cur = (uint64_t)MRS_SAFE_VAL(type) << shift;
break;
case MRS_LOWER:
user_reg = update_lower_register(user_reg, value, shift, width,
sign);
if (mrs_field_cmp(cur, new_val, shift, width, sign) < 0)
cur = new_val;
break;
case MRS_HIGHER_OR_ZERO:
if (cur == 0 || new_val == 0) {
cur = 0;
break;
}
/* FALLTHROUGH */
case MRS_HIGHER:
if (mrs_field_cmp(cur, new_val, shift, width, sign) > 0)
cur = new_val;
break;
default:
panic("Invalid field type: %d", type);
}
user_reg &= ~mask;
user_reg |= cur;
return (user_reg);
}