linux-kernel - [PATCH v1 2/2] powerpc/mmiotrace: bind ioremap and page fault to active mmiotrace

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Date: Thu, 20 Jun 2024 16:51:18 +0800
From: Jialong Yang <jialong.yang@...ngroup.cn>
To: Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	"Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>
Cc: luming.yu@...ngroup.cn,
	shenghui.qu@...ngroup.cn,
	Jialong Yang <jialong.yang@...ngroup.cn>,
	linuxppc-dev@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 2/2] powerpc/mmiotrace: bind ioremap and page fault to active mmiotrace

Hacking the code in ioremap entry and page fault handler entry to
integrate mmiotrace.

Signed-off-by: Jialong Yang <jialong.yang@...ngroup.cn>
---
 arch/powerpc/mm/fault.c      | 17 +++++++++++++++++
 arch/powerpc/mm/ioremap_64.c | 11 +++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 215690452495..b03cba73de92 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -22,6 +22,7 @@
 #include <linux/ptrace.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
+#include <linux/mmiotrace.h>
 #include <linux/interrupt.h>
 #include <linux/highmem.h>
 #include <linux/extable.h>
@@ -50,6 +51,19 @@
  * do_page_fault error handling helpers
  */
 
+/*
+ * Returns 0 if mmiotrace is disabled, or if the fault is not
+ * handled by mmiotrace:
+ */
+static nokprobe_inline int
+kmmio_fault(struct pt_regs *regs, unsigned long addr)
+{
+	if (unlikely(is_kmmio_active()))
+		if (kmmio_handler(regs, addr) == 1)
+			return -1;
+	return 0;
+}
+
 static int
 __bad_area_nosemaphore(struct pt_regs *regs, unsigned long address, int si_code)
 {
@@ -422,6 +436,9 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 	vm_fault_t fault, major = 0;
 	bool kprobe_fault = kprobe_page_fault(regs, 11);
 
+	if (unlikely(kmmio_fault(regs, address)))
+		return 0;
+
 	if (unlikely(debugger_fault_handler(regs) || kprobe_fault))
 		return 0;
 
diff --git a/arch/powerpc/mm/ioremap_64.c b/arch/powerpc/mm/ioremap_64.c
index d24e5f166723..f5f717bf35df 100644
--- a/arch/powerpc/mm/ioremap_64.c
+++ b/arch/powerpc/mm/ioremap_64.c
@@ -3,12 +3,15 @@
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <linux/mmiotrace.h>
 
 void __iomem *__ioremap_caller(phys_addr_t addr, unsigned long size,
 			       pgprot_t prot, void *caller)
 {
 	phys_addr_t paligned, offset;
 	void __iomem *ret;
+	phys_addr_t unaligned_phys_addr = addr;
+	const unsigned long unaligned_size = size;
 	int err;
 
 	/* We don't support the 4K PFN hack with ioremap */
@@ -28,8 +31,11 @@ void __iomem *__ioremap_caller(phys_addr_t addr, unsigned long size,
 	if (size == 0 || paligned == 0)
 		return NULL;
 
-	if (slab_is_available())
-		return generic_ioremap_prot(addr, size, prot);
+	if (slab_is_available()) {
+		ret = generic_ioremap_prot(addr, size, prot);
+		mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret);
+		return ret;
+	}
 
 	pr_warn("ioremap() called early from %pS. Use early_ioremap() instead\n", caller);
 
@@ -52,6 +58,7 @@ void iounmap(volatile void __iomem *token)
 	if (!slab_is_available())
 		return;
 
+	mmiotrace_iounmap(token);
 	generic_iounmap(PCI_FIX_ADDR(token));
 }
 EXPORT_SYMBOL(iounmap);
-- 
2.34.1