[PATCH] KVM: arm64: Avoid naming collision in tracing

[Mostafa Saleh <smostafa@google.com>]

When the hypervisor tracing (CONFIG_NVHE_EL2_TRACING) is disabled, it
defines a static inline stub for trace_clock().

However, trace_clock() is already declared as an extern function in
linux/trace_clock.h which is pulled in EL2 compilation.

If the file <nvhe/clock.h> is included when CONFIG_NVHE_EL2_TRACING
is disabled (by including it manually in setup.c) it will cause:
In file included from arch/arm64/kvm/hyp/nvhe/setup.c:22:

./arch/arm64/kvm/hyp/include/nvhe/clock.h:14:19: error: static declaration of ‘trace_clock’ follows non-static declaration

   14 | static inline u64 trace_clock(void) { return 0; }

      |                   ^~~~~~~~~~~

on GCC and a linker error on LLVM (it seems to change the linkage to
global)

Although that is not a problem at the moment, as no other files
include <nvhe/clock.h>. That does not seem to be the intent of
this code and that will cause issues with more users as the SMMUv3
driver.

Signed-off-by: Mostafa Saleh <smostafa@google.com>

--
I did not add Fixes tag as this is currently dormant and not breaking
anything.
---
 arch/arm64/kvm/hyp/include/nvhe/clock.h | 8 ++++----
 arch/arm64/kvm/hyp/nvhe/clock.c         | 4 ++--
 arch/arm64/kvm/hyp/nvhe/trace.c         | 4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/clock.h b/arch/arm64/kvm/hyp/include/nvhe/clock.h
index 9f429f5c0664..c2ccd0e8bf22 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/clock.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/clock.h
@@ -6,11 +6,11 @@
 #include <asm/kvm_hyp.h>
 
 #ifdef CONFIG_NVHE_EL2_TRACING
-void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc);
-u64 trace_clock(void);
+void hyp_trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc);
+u64 hyp_trace_clock(void);
 #else
 static inline void
-trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) { }
-static inline u64 trace_clock(void) { return 0; }
+hyp_trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) { }
+static inline u64 hyp_trace_clock(void) { return 0; }
 #endif
 #endif
diff --git a/arch/arm64/kvm/hyp/nvhe/clock.c b/arch/arm64/kvm/hyp/nvhe/clock.c
index a7fc61976fd0..8adefb0b696c 100644
--- a/arch/arm64/kvm/hyp/nvhe/clock.c
+++ b/arch/arm64/kvm/hyp/nvhe/clock.c
@@ -30,7 +30,7 @@ static u64 __clock_mult_uint128(u64 cyc, u32 mult, u32 shift)
 }
 
 /* Does not guarantee no reader on the modified bank. */
-void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
+void hyp_trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
 {
 	struct clock_data *clock = &trace_clock_data;
 	u64 bank = clock->cur ^ 1;
@@ -48,7 +48,7 @@ void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
 }
 
 /* Use untrusted host data */
-u64 trace_clock(void)
+u64 hyp_trace_clock(void)
 {
 	struct clock_data *clock = &trace_clock_data;
 	u64 bank = smp_load_acquire(&clock->cur);
diff --git a/arch/arm64/kvm/hyp/nvhe/trace.c b/arch/arm64/kvm/hyp/nvhe/trace.c
index e7e150ab265f..f2a32463c6c2 100644
--- a/arch/arm64/kvm/hyp/nvhe/trace.c
+++ b/arch/arm64/kvm/hyp/nvhe/trace.c
@@ -35,7 +35,7 @@ static bool hyp_trace_buffer_loaded(struct hyp_trace_buffer *trace_buffer)
 void *tracing_reserve_entry(unsigned long length)
 {
 	return simple_ring_buffer_reserve(this_cpu_ptr(trace_buffer.simple_rbs), length,
-					  trace_clock());
+					  hyp_trace_clock());
 }
 
 void tracing_commit_entry(void)
@@ -290,7 +290,7 @@ void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
 	}
 
 	/* ...we can now override the old one and swap. */
-	trace_clock_update(mult, shift, epoch_ns, epoch_cyc);
+	hyp_trace_clock_update(mult, shift, epoch_ns, epoch_cyc);
 }
 
 int __tracing_reset(unsigned int cpu)
-- 
2.55.0.795.g602f6c329a-goog