[PATCH v4 42/59] x86: Sort the MTRR table

Simon Glass sjg at chromium.org
Tue Sep 22 20:45:27 CEST 2020


At present the MTRR registers are programmed with the list the U-Boot
builds up in the same order. In some cases this list may be out of order.
It looks better in Linux to have the registers in order, so sort them,

Signed-off-by: Simon Glass <sjg at chromium.org>
---

(no changes since v1)

 arch/x86/cpu/mtrr.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/cpu/mtrr.c b/arch/x86/cpu/mtrr.c
index 2468d88a80a..08fa80f8bc7 100644
--- a/arch/x86/cpu/mtrr.c
+++ b/arch/x86/cpu/mtrr.c
@@ -19,6 +19,7 @@
 #include <common.h>
 #include <cpu_func.h>
 #include <log.h>
+#include <sort.h>
 #include <asm/cache.h>
 #include <asm/io.h>
 #include <asm/mp.h>
@@ -124,6 +125,16 @@ static int mtrr_copy_to_aps(void)
 	return 0;
 }
 
+static int h_comp_mtrr(const void *p1, const void *p2)
+{
+	const struct mtrr_request *req1 = p1;
+	const struct mtrr_request *req2 = p2;
+
+	s64 diff = req1->start - req2->start;
+
+	return diff < 0 ? -1 : diff > 0 ? 1 : 0;
+}
+
 int mtrr_commit(bool do_caches)
 {
 	struct mtrr_request *req = gd->arch.mtrr_req;
@@ -139,6 +150,7 @@ int mtrr_commit(bool do_caches)
 	debug("open\n");
 	mtrr_open(&state, do_caches);
 	debug("open done\n");
+	qsort(req, gd->arch.mtrr_req_count, sizeof(*req), h_comp_mtrr);
 	for (i = 0; i < gd->arch.mtrr_req_count; i++, req++)
 		set_var_mtrr(i, req->type, req->start, req->size);
 
-- 
2.28.0.681.g6f77f65b4e-goog



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