[PATCH v3 3/3] x86/platform/uv: Log gap hole end size

From: Mike Travis
Date: Mon Apr 04 2022 - 18:01:54 EST


Show value of gap end in the kernel log which equates to number of physical
address bits used by system. The end address of the gap holds PA bits 56:26
which gives the range up to 64PB max size with 64MB of granularity.

Signed-off-by: Mike Travis <mike.travis@xxxxxxx>
Reviewed-by: Steve Wahl <steve.wahl@xxxxxxx>
---
v2: Update patch description to be more explanatory.
---
arch/x86/kernel/apic/x2apic_uv_x.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 387d6533549a..146f0f63a43b 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -1346,7 +1346,7 @@ static void __init decode_gam_params(unsigned long ptr)
static void __init decode_gam_rng_tbl(unsigned long ptr)
{
struct uv_gam_range_entry *gre = (struct uv_gam_range_entry *)ptr;
- unsigned long lgre = 0;
+ unsigned long lgre = 0, gend = 0;
int index = 0;
int sock_min = 999999, pnode_min = 99999;
int sock_max = -1, pnode_max = -1;
@@ -1380,6 +1380,9 @@ static void __init decode_gam_rng_tbl(unsigned long ptr)
flag, size, suffix[order],
gre->type, gre->nasid, gre->sockid, gre->pnode);

+ if (gre->type == UV_GAM_RANGE_TYPE_HOLE)
+ gend = (unsigned long)gre->limit << UV_GAM_RANGE_SHFT;
+
/* update to next range start */
lgre = gre->limit;
if (sock_min > gre->sockid)
@@ -1397,7 +1400,8 @@ static void __init decode_gam_rng_tbl(unsigned long ptr)
_max_pnode = pnode_max;
_gr_table_len = index;

- pr_info("UV: GRT: %d entries, sockets(min:%x,max:%x) pnodes(min:%x,max:%x)\n", index, _min_socket, _max_socket, _min_pnode, _max_pnode);
+ pr_info("UV: GRT: %d entries, sockets(min:%x,max:%x), pnodes(min:%x,max:%x), gap_end(%d)\n",
+ index, _min_socket, _max_socket, _min_pnode, _max_pnode, fls64(gend));
}

/* Walk through UVsystab decoding the fields */
--
2.26.2