From a6a8bb1a9a58becb82dfacc7bc27cf645d0e216c Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Wed, 12 May 2021 10:55:17 +0100 Subject: [PATCH] [undi] Read TSC only when profiling Avoid using the "rdtsc" instruction unless profiling is enabled. This allows the non-debug build of the UNDI driver to be used on a CPU such as a 486 that does not support the TSC. Reported-by: Nikolai Zhubr Signed-off-by: Michael Brown --- src/arch/x86/drivers/net/undinet.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/src/arch/x86/drivers/net/undinet.c b/src/arch/x86/drivers/net/undinet.c index 9b7d6d849..43cb18bfe 100644 --- a/src/arch/x86/drivers/net/undinet.c +++ b/src/arch/x86/drivers/net/undinet.c @@ -104,6 +104,13 @@ static union u_PXENV_ANY __bss16 ( undinet_params ); SEGOFF16_t __bss16 ( undinet_entry_point ); #define undinet_entry_point __use_data16 ( undinet_entry_point ) +/* Read TSC in real mode only when profiling */ +#if PROFILING +#define RDTSC_IF_PROFILING "rdtsc\n\t" +#else +#define RDTSC_IF_PROFILING "" +#endif + /** IRQ profiler */ static struct profiler undinet_irq_profiler __profiler = { .name = "undinet.irq" }; @@ -288,14 +295,14 @@ static int undinet_call ( struct undi_nic *undinic, unsigned int function, */ profile_start ( &profiler->total ); __asm__ __volatile__ ( REAL_CODE ( "pushl %%ebp\n\t" /* gcc bug */ - "rdtsc\n\t" + RDTSC_IF_PROFILING "pushl %%eax\n\t" "pushw %%es\n\t" "pushw %%di\n\t" "pushw %%bx\n\t" "lcall *undinet_entry_point\n\t" "movw %%ax, %%bx\n\t" - "rdtsc\n\t" + RDTSC_IF_PROFILING "addw $6, %%sp\n\t" "popl %%edx\n\t" "popl %%ebp\n\t" /* gcc bug */ )