4 # Warning flags for compiling the kernel and components of the kernel.
6 # Note that the newly added -Wcast-qual is responsible for generating
7 # most of the remaining warnings. Warnings introduced with -Wall will
8 # also pop up, but are easier to fix.
10 #CWARNFLAGS= -w2 # use this if you are terribly bored
13 CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
14 -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
15 ${_wundef} ${_Wno_pointer_sign} -fformat-extensions
16 .if !defined(WITH_GCC3)
17 _Wno_pointer_sign=-Wno-pointer-sign
19 .if !defined(NO_UNDEF)
24 # The following flags are next up for working on:
28 # On the i386, do not align the stack to 16-byte boundaries. Otherwise GCC
29 # 2.95 adds code to the entry and exit point of every function to align the
30 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
31 # per function call. While the 16-byte alignment may benefit micro benchmarks,
32 # it is probably an overall loss as it makes the code bigger (less efficient
33 # use of code cache tag lines) and uses more stack (less efficient use of data
34 # cache tag lines). Explicitly prohibit the use of SSE and other SIMD
35 # operations inside the kernel itself. These operations are exclusively
36 # reserved for user applications.
38 .if ${MACHINE_ARCH} == "i386" && ${CC} != "icc"
39 CFLAGS+= -mno-align-long-strings -mpreferred-stack-boundary=2 \
40 -mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3
44 .if ${MACHINE_ARCH} == "arm"
48 # For IA-64, we use r13 for the kernel globals pointer and we only use
49 # a very small subset of float registers for integer divides.
51 .if ${MACHINE_ARCH} == "ia64"
52 CFLAGS+= -ffixed-r13 -mfixed-range=f32-f127 -fpic #-mno-sdata
57 # For sparc64 we want the medany code model so modules may be located
58 # anywhere in the 64-bit address space. We also tell GCC to use floating
59 # point emulation. This avoids using floating point registers for integer
60 # operations which it has a tendency to do.
62 .if ${MACHINE_ARCH} == "sparc64"
63 CFLAGS+= -mcmodel=medany -msoft-float
68 # For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
69 # operations inside the kernel itself. These operations are exclusively
70 # reserved for user applications.
72 .if ${MACHINE_ARCH} == "amd64"
73 CFLAGS+= -mcmodel=kernel -mno-red-zone \
74 -mfpmath=387 -mno-sse -mno-sse2 -mno-sse3 -mno-mmx -mno-3dnow \
75 -msoft-float -fno-asynchronous-unwind-tables
80 # For PowerPC we tell gcc to use floating point emulation. This avoids using
81 # floating point registers for integer operations which it has a tendency to do.
82 # Also explicitly disable Altivec instructions inside the kernel.
84 .if ${MACHINE_ARCH} == "powerpc"
85 CFLAGS+= -msoft-float -mno-altivec
90 # For MIPS we also tell gcc to use floating point emulation and
91 # disable MIPS DSP ASE Instruction set.
93 .if ${MACHINE_ARCH} == "mips"
94 CFLAGS+= -msoft-float -mno-dsp
99 # GCC 3.0 and above like to do certain optimizations based on the
100 # assumption that the program is linked against libc. Stop this.
103 CFLAGS+= -nolib_inline
105 CFLAGS+= -ffreestanding
115 .if ${MK_SSP} != "no" && ${CC} != "icc" && ${MACHINE_ARCH} != "ia64" && \
116 ${MACHINE_ARCH} != "arm" && ${MACHINE_ARCH} != "mips"
117 CFLAGS+= -fstack-protector